RESUMEN
1. This experiment determined the effect of increasing mobility in broiler chickens by placing barrier perches between feeders and drinkers. In addition, the limitation of early weight gain by dietary energy and protein dilution on some welfare parameters, tibiotarsus measurements, fear and mobility level was examined.2. A total of 504 male, one-day-old broiler chickens (Ross 308) were randomly allocated to four treatments with three replicate pens per treatment and 42 broiler chickens per pen as a 2 × 2 factorial arrangement. Treatments included feeding the basal control diet between 0-42 days or a diet diluted by 10% energy and 20% crude protein fed between 0-21 d, with the control diet fed between 22-42 d. The second factor was the presence or absence of barrier perches. All treatments were allocated as a completely randomised design. Welfare parameters (foot pad dermatitis, hock burn, gait score, feather score, breast blister), tibiotarsus measurements (bone mineral content, bone mineral density, fluctuating asymmetry and relative fluctuating asymmetry), tonic immobility and mobility level were recorded.3. Results showed that access to a barrier perch and the diluted diet increased the mobility in broiler chickens. However, access to a barrier perch had no significant effect on tibiotarsus and welfare parameters. Broiler chickens had better gait scores (P < 0.05) and lower foot pad dermatitis incidence (P < 0.01) in groups fed the diluted diet. The diluted diet had no significant effect on bone mineral density but reduced the tibiotarsus bone mineral content (P < 0.05).4. In conclusion, the diluted diet provided positive effects in terms of leg health due to weight gain limitations in the early period, thus improving broiler chicken welfare.