Nigerian indigenous hens show more discomfort-related behavior with visual separation than physical separation from their chicks: An exploratory study.

The Nigerian indigenous hens exhibit their full natural behavior repertoires, including maternal care. The strong maternal bond between the hen and her chicks is established prior to hatching. Maternal care of chickens is essential for both exotic and indigenous chickens. This study compared the behaviors of six hen-chick pairs in a physical (PHY) and visual (VIS) separation test for 10 min. All the six hen-chick pairs were subjected to PHY separation on the 8th day of post-hatch and a VIS separation on the 12th day of post-hatch. The PHY separation involved the use of a wire mesh to separate the hen from her chicks, while the VIS separation involved the use of a trampoline to separate the hen from her chicks. The hen's behavior was recorded during the 10-min separation period. Behaviors recorded included sitting, body shaking, pecking, movements toward the chicks, jumping, pacing, defecation, movements away from the chicks, and preening. We further grouped these nine behaviors into two categories: discomfort-related (pacing, movement toward chicks, body shaking, defecation, and jumping) and comfort-related (sitting, pecking, preening, and movement away from the chicks) behaviors. Before and after each separation, the hens were gently restrained, and a drop of blood was sampled from the wing vein to determine the blood glucose level. Their heart rate and eye temperature were also measured. A two-related samples test (Wilcoxon) was used to compare the behavior of the hens when subjected to the PHY and VIS separation. Eight out of the nine behaviors monitored did not differ between the separation types. However, the frequency of pacing by the hens was greater (z = -2.201, P = 0.028) in the VIS separation than in the PHY separation. Also, discomfort-related behavior was greater (t (5) = -2.717, P = 0.042) during the VIS separation than the PHY separation. Comfort-related behavior did not differ between the separation types. The change in eye temperature, heart rate, and blood glucose was similar in the two separation types. In conclusion, Nigerian indigenous hens displayed more discomfort-related behavior to the VIS separation from their chicks, but this was not associated with physiological responses indicative of stress.

An exploratory study on differences in maternal care between two ecotypes of Nigerian indigenous chicken hens.

The Yoruba (YRE) and Fulani (FLE) are the two notable indigenous chicken ecotypes in Nigeria. They exhibit broodiness and post-hatch care of their chicks. Studies on welfare, productivity, and maternal behaviors of these two ecotypes are scarce, hence the need for this study. Separate flocks of these ecotypes were housed intensively and hens that showed broodiness (ten YRE and five FLE) were monitored. Brooding behaviors were monitored for 3 days in the 1st and 2nd weeks of brooding and daily in the 3rd week of brooding for 6 h/day (07:00-09:00 h, 11:00-13:00 h, and 15:00-17:00 h). During brooding, surface body temperatures (eye, brood patch and under the wings), egg temperature and body weight of the hens were measured. Chicks hatched (44 chicks from the YRE and 24 chicks from the FLE) by these hens were subjected to tonic immobility tests on the 7th, 14th, and 21st days post-hatch and to a simulated predator test on the 8th, 15th, and 22nd days post-hatch to determine their level of fear. In each ecotype, brooding behaviors did not change over the three weeks, but the YRE hens spent longer time sitting on their eggs at the 2nd (U = 5.000, z = -2.454, P = 0.014) and 3rd (U = 9.000, z = -1.961, P = 0.050) week of brooding. The surface body temperatures of both ecotypes, egg temperature, and relative weekly weight loss were similar over the brooding period, but relative weekly weight loss was greater (P < 0.05) at the 3rd than 1st and 2nd week of brooding. The surface body temperatures were positively correlated (P < 0.01) with egg temperature. In both ecotypes, attempts to induce and duration of tonic immobility were similar over the test periods but on the 7th day post-hatch, the duration of tonic immobility was longer (U = 323.000, z = -2.632, P = 0.008) and on the 14th day post-hatch, the number of attempts to induce tonic immobility was less (U = 332.000, z = -2.630, P = 0.009) in the YRE chicks. In conclusion, YRE hens sat more on the eggs and their chicks were more fearful.

Effect of acute heat stress on cognitive performance of chickens in a feed-related discriminant task.

Little is known about immediate and long-lasting effect of acute heat stress on chicken cognition. Thirty-five, 9-week-old birds were trained to differentiate two cone colours; white (rewarded, R; with feed underneath) and black (unrewarded, UR; empty). The sixteen birds that learnt the task were randomly assigned to three temperature regimens (TR: 22-24 °C (control), 30-32 and 36-38 °C for 3h/day) for three consecutive days during which rectal (RT), wing (WT) and eye (ET) temperatures were monitored. After the 3 h of exposure, birds were allowed to rest for 1 h before the commencement of the discriminant task. The latencies to open the cones (R and UR) and proportion of cones opened were recorded. A long-lasting effect was tested a week after exposure to TR. TR had a significant effect on RT, WT and ET. The motivation to turn over R cones was weaker in birds exposed to 36-38 °C than birds exposed to 22-24 °C. Also, the proportion of R cones opened were fewer in birds that experienced TR of 36-38 °C compared to birds exposed to 22-24 °C and 30-32 °C specifically on two out of the three cognitive test days (Days 1 and 3). Latency and proportion of UR cones opened was not affected by TR. RT, WT and ET were all negatively and significantly correlated with latency to open the UR cones. Previous exposure of birds to three TR had no effect on the latency to open both cones but the proportion of R cones opened was greater in birds exposed to 30-32 °C compared to the 22-24 °C birds. In conclusion, an immediate (36-38 °C) and long-lasting effect (30-32 °C) of acute heat stress was associated with a weak motivation to perform feed related discrimination task.

Genetic diversity, phylogeographic structure and effect of selection at the mitochondrial hypervariable region of Nigerian chicken populations.

In this study, the maternal genetic diversity, phylogenetic relationship and effect of natural selection on indigenous chickens from Nigeria were assessed. A total of 397-bp fragment of the mitochondrial DNA (mtDNA) D-loop region of 171 indigenous chickens from four populations of Nigeria and four commercial egg line strains (two Anak titan, one Giriraja and one Yaffa) as out-groups were analysed. Thirty-one haplotypes (28 from Nigerian chickens and three from commercial strains) and 34 polymorphic sites were identified. The mean haplotypic and nucleotide diversity were found to be 0.39 ± 0.05 and 0.02 ± 0.02, respectively. Majority of Nigerian chicken haplotypes observed were grouped into haplogroup D which originated from Indian subcontinent, suggesting a single maternal lineage. Genetic variation within and between populations accounted for 97.30 and 2.70% of the total genetic variation, respectively, which is in agreement with a recent and maternal founding effect. High number (4) of negatively selected sites observed based on single likelihood ancestral counting (SLAC) model indicated that the sampled Nigerian chicken populations were undergoing purifying selection. This study concluded that there was relatively high genetic diversity and differentiation, thus, this information will probably paveway for further evaluation studies, preservation and improvement of Nigerian chickens as genetic resources towards ensuring food security.