Effects of colored light-emitting diode illumination on behavior and performance of laying hens.

The best method for lighting poultry houses has been an issue for many decades, generating much interest in any new systems that become available. Poultry farmers are now increasingly using colored LED (light-emitting diodes) to illuminate hen houses (e.g., in Germany, Austria, the Netherlands, and England). In Switzerland all newly installed systems are now equipped with LED, preferably green ones. The LED give monochromatic light from different wavelengths and have several advantages over conventional illuminants, including high energy efficiency, long life, high reliability, and low maintenance costs. The following study examines the effects of illumination with white, red, and green LED on behavior and production parameters of laying hens. Light intensities in the 3 treatments were adjusted to be perceived by hens as equal. Twenty-four groups of 25 laying hens were kept in identical compartments (5.0 × 3.3 m) equipped with a litter area, raised perches, feed and drinking facilities, and nest boxes. Initially, they were kept under white LED for a 2-wk adaptation period. For the next 4 wk, 8 randomly chosen compartments were lit with red LED (640 nm) and 8 others with green LED (520 nm). Behavior was monitored during the last 2 wk of the trial. Additionally weight gain, feed consumption, onset of lay, and laying performance were recorded. The results showed minor effects of green light on explorative behavior, whereas red light reduced aggressiveness compared with white light. The accelerating effect of red light on sexual development of laying hens was confirmed, and the trial demonstrated that this effect was due to the specific wavelength and not the intensity of light. However, an additional effect of light intensity may exist and should not be excluded.

Attitudes of Swiss consumers towards meat from entire or immunocastrated boars: a representative survey.

Male piglets are castrated in order to prevent boar taint in pork. The surgical intervention is currently done without anaesthesia. Growing public concern about the welfare issue of this procedure forces the meat industry to evaluate alternative methods. The acceptance of such methods was studied in Switzerland within a large representative survey on the image of Swiss meat. Five questions were aimed at our subject. It was found that only a small part of the population has actually experienced boar taint. Nevertheless, the majority would not buy products made from tainted meat even if the absence of any perceivable boar taint and identical quality with current products could be guaranteed. The acceptance of meat from immunocastrated animals was low. Among the proposed four alternative methods, the production of entire males (with two options regarding processing of the tainted meat), immunocastration and castration with anaesthesia, only the last one seems to be acceptable to the interviewees.

Comparison of the prelaying behavior of nest layers and litter layers.

The Swiss Animal Welfare Act decrees that the housing conditions of farm animals must guarantee animal welfare. In the process of developing a method to test nest boxes for their suitability for laying hens, we conducted an investigation using preference testing. It was aimed at verifying the occurrence of different types of layers within the same laying strain and to investigate the choice of a nest site. At the onset of lay, 24 individually housed hens were given the choice of 2 nest sites: a nest box or a litter tray. The chosen nest site and the behavior of the hen, 1 h prior to oviposition, were recorded at 3 stages during the period in which the first 20 eggs were laid. The majority (17) of the hens laid consistently in the nest box, and 7 hens laid consistently in the litter tray. Litter layers spent more time exploring during the hour prior to oviposition than did nest layers, and their final nest visit (when an egg was laid) was shorter. There was no significant difference in the number of entries into the chosen nest site between layers of the 2 types. As expected, the level of restlessness of hens decreased with laying experience. In the hour prior to oviposition, the frequency of foraging and resting increased, whereas the frequency of exploring and nest seeking decreased, and the number of nest-site visits declined. We conclude that there may be at least 2 different types of laying hens that show different nest-site preferences, with concomitantly different prelaying behavior.

Effect of the analgesic butorphanol on activity behaviour in turkeys (Meleagris gallopavo).

During fattening, the bodyweight of modern broad-breasted turkeys increases considerably within a very short space of time. In particular, the breast muscles increase disproportionately. This leads to a disadvantageous distribution in weight, and as a consequence, to a disturbed leg position and skeletal deformations like antitrochanteric degeneration, tibial dyschondroplasia, bending, twisting and rotation of the tibia, osteochondrosis, osteomyelitis, rickets, and epiphyseolysis of the femoral head increases. This cases of degenerative joint disease cause severe pain in humans and there are indications that this is also true for turkeys. The purpose of this study was to determine if behaviour indicative of such pain in turkeys of the B.U.T. Big 6 breeding line could be attenuated by administering a quick-acting analgesic, butorphanol. Twelve pairs of turkeys were tested at the ages of 7 and 12 weeks. One bird in each pair received an analgesic opioid injection, while the other one received a control injection of physiologically balanced saline solution. The time the birds spent putting weight on their legs, i.e., 'walking' and 'standing' and the distance covered by the birds were recorded during the 30 min periods before and after the application of the drug. At week seven the treated birds spent significantly more time putting weight on their legs than control birds. At week 12, the same tendency was observed. No significant differences were found in the distances covered by the animals. It is concluded that fattening turkeys reduce the time they are putting weight on their legs because these behaviours may be associated with pain.

Effects of feeding corticosterone and housing conditions on feather pecking in laying hens (Gallus gallus domesticus).

Feather pecking (FP) and cannibalism in laying hens are disadvantageous to the well-being of the birds. We investigated whether stress could be proposed as a trigger for the development of this abnormal behavior. From Week 11 to 19 after hatching, 16 groups of 15 or 16 hens (white Lohman Selected Leghorn hybrids) were kept in pens with or without foraging material (litter) and fed a diet containing corticosterone (C, 1.5 mg/bird/day) or no C. Birds fed on C had reduced values for weight gain and egg production, prolonged tonic immobility (TI), higher heterophil/lymphocyte ratios (H/L) and higher serum C concentrations. On litter, C-fed birds developed significantly higher rates of FP than when not fed C. However, birds kept on slats also developed high rates of FP but without being fed C. Feeding C to these birds did not significantly further increase the rates of FP. We concluded that FP may develop as a response to increased blood C concentrations, but that housing conditions restricted in relation to foraging material, may as well induce FP in the absence of increased C levels.

Reducing feather pecking when raising laying hen chicks in aviary systems.

Aviary systems for laying hens offer several advantages over battery cages. However, pecking the feathers of conspecifics remains a serious problem that negatively affects the welfare of the birds as well as the economy of a farm. From experimental studies with small groups, it has been shown that feather pecking and foraging behaviour are related and that both behaviour are influenced by early access to litter substrate. We, therefore, hypothesised, that feather pecking in aviaries can be reduced with an adequate management in the first 2 weeks of life.Each of seven pens on six commercial poultry farms, was divided into two identical compartments (matched pair design). In one of the compartments (experimental compartment) chicks were reared for the first 2 weeks of life with access to litter (wood shavings, in one case with additional straw), while the chicks in the other compartment (control) were kept on a plastic grid. Thereafter, all chicks had unrestricted access to litter and there were no differences between the two compartments neither in housing conditions nor in management procedures.Chicks in the experimental compartments spent significantly more time foraging (week 5), showed significantly less feather pecking (weeks 5 and 14) and significantly fewer birds had damaged tail feathers (weeks 5 and 14).The study demonstrates that in aviaries, under commercial conditions, early access to litter substrate has a significant effect on the development of feather pecking. In order to reduce feather pecking and to increase foraging behaviour, it is recommended that laying hen chicks raised in aviary systems do get access to litter from day 1 on.

Are genetic differences in foraging behaviour of laying hen chicks paralleled by hybrid-specific differences in feather pecking?

Feather pecking is a behavioural disorder in laying hens which consists of pecking the feathers of conspecifics, causing feather damage or even injuries to the skin. Its development can be explained by redirection of foraging behaviour. While the occurrence of feather pecking strongly depends on the kind of housing condition, it is also known that there are strain differences in the tendency to feather peck. From the inverse relation between feather pecking and foraging behaviour found earlier, we hypothesised that genetically determined differences in foraging behaviour could be responsible for the observed differences in feather pecking between strains.In a first experiment we tested whether there are differences in the foraging behaviour of two hybrids. As hybrids, we used Lohman selected leghorn (LSL) and Dekalb; eight groups of 20 1-day old chicks each. They were kept in enriched pens (265cmx90cm) with a litter area (200cmx90cm) consisting of wood-shavings, chaff, straw, polystyrene blocks, sand area (65cmx90cm) and elevated perches. Behavioural observations were carried out in week 4. In a subsequent experiment with the same birds we tested how the foraging behaviour of the two hybrids differed when housing conditions were changed from enriched to restricted and to what extent they developed feather pecking. A 2x2 factorial design with hybrid (LSL, Dekalb) and housing condition (restricted, enriched) as factors and with four replicates of each factor combination was used. Half of the pens of each hybrid were changed from enriched to restricted housing conditions by covering the litter area with slats. Behavioural observations were carried out in weeks 5 and 6.In experiment 1, LSL and Dekalb spent the same amount of time foraging, but Dekalb spent significantly more of that time with pecking and hacking at the polystyrene blocks. On the other hand, LSL spent significantly more time at the feeding troughs and rested significantly less than Dekalb. In the restricted environment of experiment 2, again, the total foraging time did not differ between hybrids, but LSL chicks spent significantly less time scratching, while Dekalb spent significantly more time moving. Both hybrids developed feather pecking but LSL showed significantly higher rates than Dekalb.Our results demonstrate genetic differences in the foraging behaviour and in the way hybrids cope with the change in housing condition from enriched to an environment that is restricted in relation to foraging possibilities. We conclude that the results support the hypothesis put forward that genetic differences in foraging behaviour could be the basis for the genetic influence in the development of feather pecking.

No mutagenic or recombinogenic effects of mobile phone fields at 900 MHz detected in the yeast Saccharomyces cerevisiae.

Both actively growing and resting cells of the yeast Saccharomyces cerevisiae were exposed to 900-MHz fields that closely matched the Global System for Mobile Communication (GSM) pulsed modulation format signals for mobile phones at specific absorption rates (SAR) of 0.13 and 1.3 W/kg. Two identical anechoic test chambers were constructed to perform concurrent control and test experiments under well-controlled exposure conditions. Using specific test strains, we examined the genotoxic potential of mobile phone fields, alone and in combination, with a known genotoxic compound, the alkylating agent methyl methansulfonate. Mutation rates were monitored by two test systems, a widely used gene-specific forward mutation assay at CAN1 and a wide-range assay measuring the induction of respiration-deficient (petite) clones that have lost their mitochondrial function. In addition, two further assays measured the recombinogenic effect of mobile phone fields to detect possible effects on genomic stability: First, an intrachromosomal, deletion-formation assay previously developed for genotoxic screening; and second, an intragenic recombination assay in the ADE2 gene. Fluctuation tests failed to detect any significant effect of mobile phone fields on forward mutation rates at CAN1, on the frequency of petite formation, on rates of intrachromosomal deletion formation, or on rates of intragenic recombination in the absence or presence of the genotoxic agent methyl methansulfonate.

Is there social transmission of feather pecking in groups of laying hen chicks?

Feather pecking is an abnormal behaviour where laying hens peck the feathers of conspecifics, damaging the plumage or even injuring the skin. If it occurs in a flock, more and more birds show it within a short period of time. A possible mechanism is social transmission. Several studies have shown that laying hen chicks, Gallus gallus domesticus, are able to modify their own behaviour when observing the behaviour of other chicks, for example, when feeding and foraging. As there is good experimental evidence that feather pecking originates from foraging behaviour, we hypothesized that feather pecking could also be socially transmitted. To test this, we reared 16 groups of 30 chicks. After week 4, the birds were regrouped into 16 groups of 20 chicks into each of which we introduced either five chicks that showed high frequencies of feather pecking or, as controls, five chicks that had not developed feather pecking. We then determined the feather-pecking rate and the frequency of foraging, dustbathing, feeding, drinking, preening, moving, standing and resting of all birds in a group. Data from the introduced birds were analysed separately and excluded from the group data. Chicks in groups with introduced feather-pecking chicks had a significantly higher feather-pecking rate than chicks in the control groups. In addition, birds in groups with introduced feather peckers showed significantly lower foraging frequencies than those in the control groups, although the housing conditions were identical and there were no differences in either the number or the quality of the stimuli relevant to foraging behaviour. The study therefore suggests that feather pecking is socially transmitted in groups of laying hen chicks. Copyright 2000 The Association for the Study of Animal Behaviour.

Analysis of risk factors for the occurrence of feather pecking in laying hen growers.

1. Potential risk factors for the occurrence of feather pecking in laying hen growers raised under commercial conditions were investigated on Swiss farms with more than 500 rearing places. On-farm interviews were conducted on a sample of 64 flocks which represented 42.6% of all farms concerned. 2. All variables considered were dichotomised and their univariate correlation with the occurrence of feather pecking was tested for significance at P <0.20 using chi2 tests. Logistic regression with backward elimination was then used with the significant variables to identify the potentially most important factors influencing feather pecking. These variables included stocking density, light intensity, intensity of care, access to elevated perches, access to a roofed and littered outdoor area ('bad weather run'), time of access to the feeding facilities of the housing system, stocking density in the restricted area at the beginning of the rearing period, additional open feeding areas in the beginning and air quality. 3. The final model contained stocking density and access to elevated perches as significant factors (P<0.05). Flocks kept in high density (> or = 10 birds per m2) and with no access to elevated perches were 6.4 (95% Confidence interval 1.7 to 24.2) and 4.0 (95% Confidence interval 1.2 to 12.9) times more likely to be affected by feather pecking, respectively. 4. The study identified 2 risk factors for the occurrence of feather pecking in flocks of laying hen growers reared under commercial conditions. It is concluded that in order to reduce feather pecking chicks should be reared at low density and with access to elevated perches.

The effect of quality and availability of foraging materials on feather pecking in laying hen chicks.

Feather pecking resulting in feather damage, injuries and mortality causes severe welfare problems in laying hens. In the present study, we tested whether there is an inverse relationship between feather pecking and foraging behaviour (exploratory and manipulative behaviour away from the feeder). Forty-eight groups of 30 or 31 chicks, Gallus gallus domesticus, were reared in pens and provided with different types of foraging material. Feather pecking and foraging behaviour were quantified when the chicks were 4 and 5 weeks of age. In experiment 1, chicks with access to long-cut straw showed more foraging behaviour and less feather pecking than chicks that were provided with the same straw but in shredded form. On the other hand, there was no difference in foraging behaviour and feather pecking between chicks reared with access to long-cut straw and polystyrene blocks. In experiment 2, the importance of the form of the foraging material was confirmed. Chicks provided with polystyrene blocks performed more foraging behaviour and less feather pecking than chicks with access to polystyrene beads. The provision of an area with a layer of wood-shavings to promote scratching behaviour had no significant effect, however, on the incidence of feather pecking. In experiment 3, polystyrene blocks and beads were offered during the whole day or only in the morning. Both the quality and the availability of the foraging materials had a significant effect on foraging behaviour and a significant but opposite effect on feather pecking. Focal animal observations showed that the chicks performed different types of foraging behaviour at polystyrene blocks and beads. This suggests that not only the quantity but also the quality of foraging behaviour elicited by a given material may be important to prevent the development of feather pecking. Feather pecking should thus be considered as redirected foraging behaviour. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.

Feather pecking in growers: a study with individually marked birds.

1. The aim of the present study was to investigate whether individual birds specialise in feather pecking. Growers were individually marked and reared in groups of 30 or 31 in pens with a slatted floor. At an age of 4 to 6 weeks feather pecking was frequent in all pens. 2. On average 83% of all group members (10 groups, experiment 1) were recorded at least once as initiator of a feather pecking interaction. In each group 2 to 6 individuals feather pecked more than twice as often as the average for the group, and were defined as 'high rate peckers'. They initiated 39% of all recorded feather pecking interactions. 3. Every interaction was classified (with increasing intensity) as pecking, pinching, pulling or plucking. Compared to the others, 'high rate peckers' had more of their feather pecking classified as plucking and less classified as pecking. 4. There was no evidence that particular individuals specialised in pecking at other specific birds, at specific areas of the body or at birds engaged in specific activities. 5. Growers (3 groups, experiment 2) that had just feather pecked engaged in more feather pecking during a subsequent 2-min focal observation than control birds that had not pecked before the start of the observation. 6. It was concluded that feather pecking interactions are clustered in time and that the behaviour is not performed by just a few members of a group. However, some individuals are characterised by relatively high rates and more severe forms of feather pecking.

Feather pecking in domestic chicks: its relation to dustbathing and foraging

Feather pecking is a serious problem in poultry housing, as it may lead to feather damage, injuries and even mortality. We tested predictions of the two prevalent hypotheses claiming that feather pecking is related to dustbathing and foraging, respectively. Forty-two groups of 30 laying hen chicks, Gallus gallus domesticuswere reared in pens with a slatted floor. Access to sand as a dustbathing substrate and straw as a foraging substrate was varied between groups. The rate of feather pecking was measured in early development up to week 7. The provision of a sand area did not prevent the chicks from developing high rates of feather pecking that caused injuries. Chicks that had access to sand from day 10 showed higher rates of feather pecking than chicks that had access to sand from day 1. The provision of straw to chicks that had developed high rates of feather pecking led to a decrease in this behaviour. Chicks that could use both sand and straw from day 1 on did not show high rates of feather pecking, and no injuries were observed in these groups. There was no significant difference in dustbathing activity between housing conditions characterized by high or low rates of feather pecking. On the other hand, foraging activity was inversely related to the rate of feather pecking, and the occurrence of feather pecking could be delayed from week 4 to week 7 by postponing procedures that led to changes in foraging behaviour. In conclusion, the results show that the presence of an appropriate substrate for dustbathing does not prevent domestic chicks from developing feather pecking. On the other hand, housing conditions that promote foraging behaviour are effective in reducing and preventing feather pecking.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour

Extremely high frequency electromagnetic fields at low power density do not affect the division of exponential phase Saccharomyces cerevisiae cells.

Exponentially growing cells of the yeast Saccharomyces cerevisiae were exposed to electromagnetic fields in the frequency range from 41.682 GHz to 41.710 GHz in 2 MHz increments at low power densities (0.5 microW/cm2 and 50 microW/cm2) to observe possible nonthermal effects on the division of this microorganism. The electronic setup was carefully designed and tested to allow precise determination and stability of the electromagnetic field parameters as well as to minimize possible effects of external sources. Two identical test chambers were constructed in one exposure system to perform concurrent control and test experiments at every frequency step under well-controlled exposure conditions. Division of cells was assessed via time-lapse photography. Control experiments showed that the cells were dividing at submaximal rates, ensuring the possibility of observing either an increase or a decrease of the division rate. The data from several independent series of exposure experiments and from control experiments show no consistently significant differences exposed and unexposed cells. This is in contrast to previous studies claiming nonthermal effects of electromagnetic fields in this frequency range on the division of S. cerevisiae cells. Possible reasons for this difference are discussed.

Effects of microwave and radio frequency electromagnetic fields on lichens.

The effects of electromagnetic fields on lichens were investigated. Field experiments of long duration (1-3 years) were combined with laboratory experiments and theoretical considerations. Samples of the lichen species Parmelia tiliacea and Hypogymnia physodes were exposed to microwaves (2.45 GHz; 0.2, 5, and 50 mW/cm2; and control). Both species showed a substantially reduced growth rate at 50 mW/cm2. A differentiation between thermal and nonthermal effects was not possible. Temperature measurements on lichens exposed to microwaves (2.45 GHz, 50 mW/cm2) showed a substantial increase in the surface temperature and an accelerated drying process. The thermal effect of microwave on lichens was verified. The exposure of lichens of both species was repeated near a short-wave broadcast transmitter (9.5 MHz, amplitude modulated; maximum field strength 235 V/m, 332 mA/m). No visible effects on the exposed lichens were detected. At this frequency, no thermal effects were expected, and the experimental results support this hypothesis. Theoretical estimates based on climatic data and literature showed that the growth reductions in the initial experiments could very likely have been caused by drying of the lichens from the heating with microwaves. The results of the other experiments support the hypothesis that the response of the lichens exposed to microwaves was mainly due to thermal effects and that there is a low probability of nonthermal effects.