Effects of age and stocking density on leg weakness in broiler chickens

ABSTRACT The effects of stocking density (STD) on leg weakness in broiler chickens was assessed in two trials. The interaction between age and STD on leg weak-ness was further evaluated in one trial. In Trial 1, walking ability was assessed at 28, 42, and 49 d of age. Birds were stocked at 833, 625, or 435 cm2 per bird. In Trial 2, birds were stocked at 625 or 455 cm2 per bird and assessed for tibial dyschondroplasia (TD) by radiographic examina-tion at 28 d and walking ability at 35 d. Foot pad burn, hock burn, and angulation of the hock joint were also assessed at slaughter on Day 42. Body weight was mea-sured during both trials. At 4 wk of age, leg weakness was a relatively minor problem; few severely lame birds had a gait score (GS) of 4 or 5 at any density. However, 2 wk later, the birds had substantially poorer walking (Key words: leg problems, tibial dyschondroplasia, stocking density, age, body weight