Behaviour and animal welfare indicators of broiler chickens housed in an enriched environment.

The present study aimed to assess the influence of adding straw bales, step platforms, and laser projectors as environmental enrichment resources on the behaviour and welfare indicators of broiler chickens (Gallus gallus domesticus). A sample of 4,000 day-old male Cobb® 500 birds was used. The experimental treatments consisted of No Environmental Enrichment (NEE)-similar to a conventional environment; and Environmental Enrichment (EE)-environment enriched with straw bales, step platforms, and laser projectors, with four replicates per treatment of 500 animals. Behavioural characteristics (ethological observation through cameras, grab test, and modified touch test) and animal welfare indicators (pododermatitis and dorsal cranial myopathy) were assessed. The birds submitted to the EE treatment exhibited greater exploratory activity and expression of behaviours associated with comfort and welfare, whereas those in the NEE group were less active. Locomotion and play fighting behaviour decreased and behaviours associated with comfort increased as age advanced. The frequencies of interaction with laser spots and birds lying around straw bales were the highest in the 1st week (P<0.01). The behaviours of pecking at straw bales (P<0.0004), using the step platforms (P = 0.0001) and being on top of straw bales (P<0.0002) gradually increased. The chickens accessed the feeding troughs the most in the period of 0800 hours (P<0.0001) and expressed the highest frequencies of behaviours associated with comfort in the 1400 hours and 1700 hours periods. The birds in the EE group were calmer in face of human presence and touch and scored higher in animal welfare indicators. Adding straw bales, step platforms, and laser projectors increased locomotion, reduced expression of fear, and improved animal welfare indicators of broiler chickens.

Effects of analgesic and noise stimulus in gait score assessment.

This experiment was carried out aiming to assess walking manner and speed of broiler chickens with different gait scores (GS), with or without sound stimulus, and with or without administration of analgesic. To that end, 1,000 birds were evaluated by the GS test and 74 were selected for walking speed analyses. Weight at slaughter and breast yield values were obtained for comparisons. Walking speed analyses, both with and without analgesic and with and without stimulus were performed. Non-parametric statistics was applied to the GS data that did not meet the assumptions of the statistical model (normality and homogenicity) using Fisher's exact test according to the data behavior (P<0.05). The analyses of data on speed, weight at slaughter, and breast yield were evaluated by ANOVA and compared by Tukey's test (P<0.05). Walking speed differed after acoustic stimulus with or without administration of metamizole sodium. Body weight was also different in each GS. It is thus concluded that the birds may feel discomfort when their GS is higher than 0, but that such discomfort may be suppressed when they are stimulated to walk.