Thesis - Behaviour and animal welfare indicators of broiler chickens housed in an enriched environment
The objective of this study was to evaluate the economic viability of implementing environmental enrichment, as well as to verify its influence on the animal welfare and productivity of broilers. 4000 male one-day-old Cobb® Slow birds from a commercial hatchery were used. The birds were housed in climate controlled poultry barn in a fully automated system with negative pressure ventilation, being delimited longitudinally, maintaining a feeder line and a drinker line to each side. Experimental treatments consisted: No Environmental Enrichment (NEE) - environment similar to that found in commercial poultry houses; and Environmental Enrichment (EE) - environment similar to that found in commercial poultry houses, but enriched with straw bales (75 x 42 x 30 cm), step platforms (60 x 60 x 14 cm) and laser light projectors, being 2000 birds by treatment. The productive characteristics (performance, carcass and parts yield, economic food efficiency, and economic analysis), behavioral characteristics (ethological observation by cameras, catch and approach test) and assessments of welfare indicators (pododermatitis and dorsal cranial myopathy) were evaluated. The birds in the NEE treatment showed greater weight gain (P=0.0011) and higher carcass yield (P=0.0371), while the birds in the EE treatment showed lower FCR and greater viability. The animals in the EE treatment showed higher PEF, EFE and profitability 3.47% lower than the animals in the NEE treatment. The birds in the EE treatment showed greater exploratory activity (P<0.0001), while the SEA treatment showed more animals lying and resting (P<0.0001). There was a gradual reduction in locomotion with increasing age and an increase in behaviors associated with comfort. Laser light projectors were more used in the 1st week (P<0.0001), while straw bales and step platforms were more used with increasing age. The birds in the EE treatment showed better frequencies in the catch and approach tests and lower incidences of pododermatitis and dorsal cranial myopathy. It is concluded that the implementation of straw bales, step platforms and laser light projectors for broilers, in an environment similar to the commercial one, does not increase production costs too much and is economically viable, in addition to increasing locomotor activity, reduce the expression of fear and reduce the incidence of pododermatitis and dorsal cranial myopathy in broilers.