Does environmental enrichment improve performance, morphometry, yield and weight of broiler parts at different ages?/Enriquecimento ambiental melhora desempenho, morfometria, rendimento e peso das partes de frangos em diferentes idades?

HIGHLIGHTS: The use of perch did not change feed intake, weight gain and feed conversion. The morphometry and weight of the drumstick + thighs, feet and chest increased in perch from the last week of rearing. The use of a perch showed a differentiated and hyperalometric growth for the drumstick + thighs and chest. The inclusion of environmental enrichment in conventional broiler rearing can increase mobility, bone mass and muscle. This research aimed to evaluate the use of environmental enrichment in the rearing of broilers at different ages and its influence on performance, morphometry, yield and weight of the parts. It was used the completely randomized design in split-plot scheme, being the plots the treatments presence (T1) and absence (T2) of environmental enrichment and the subplots the broiler ages (1, 7, 14, 21, 28, 35 and 42 days), with 56 chicks in each treatment (T1 and T2). Data obtained were analyzed by the linear effect model of fixed effects and compared by Tukey's test of means. The animals were raised in a controlled environment, divided into four boxes with dimensions: 1.5 X 1.0 X 0.7 m, containing rice straw bed. In T1 a ladder with a perch on top was used, distributed every 1.5 m2. Environmental enrichment used did not influence broiler's zootechnical performance. Broilers' morphometric properties, parts weight and body weight increased due to environmental enrichment and, improvement was observed in chicks rearing's final phase. The environmental enrichment was beneficial for muscle and bone mass gain in the main commercial parts of the chicken carcass, in addition to reducing the allometric coefficient of the breasts in chickens. Key words: poultry farming, perch, chicks movement A inclusao do enriquecimento ambiental na criacao convencional dos frangos de corte pode causar aumento na mobilidade, massa ossea e musculos. O objetivo desta pesquisa foi avaliar o uso do enriquecimento ambiental na criacao de frangos de corte em diferentes idades e sua influencia no desempenho, morfometria, rendimento e peso das partes. Foi utilizado o delineamento inteiramente casualizado em esquema de parcelas subdivididas, sendo que, nas parcelas foram alocados os tratamentos presenca (T1) e ausencia (T2) de enriquecimento ambiental e nas subparcelas as idades dos frangos (1, 7, 14, 21, 28, 35 e 42 dias), com 56 aves em cada tratamento (T1 e T2). Os dados obtidos foram analisados pelo modelo linear de efeitos fixos e comparados pelo teste de medias de T