Live body weight, breast condition and welfare outcomes of a white layer flock housed in conventional cages

This study was conducted to determine the effects of body weight, age and breast condition on animal welfare in a white layer flock housed in a traditional cage system in Bursa Uludağ University Faculty of Veterinary Medicine, Animal Health and Animal Production Research and Application Center Poultry Unit. Animal welfare levels were monitored in 450 laying hens (Lohman LSL) from 59 weeks to 67 weeks of age. At the beginning of the experiment, the animals were divided into three groups according to their live weights; as light (1100-1400 g), medium (1400-1700 g), and heavy (1700-2000 g). The animals in each weight group were further divided into two groups according to their breast condition (width), those between 2.0-4.4 cm and those between 4.5-6.0 cm. Hens were kept under standard conditions for commercial layers during the experiment, with five layers in each cage compartment. The level of keel bone deviation and plumage quality in four different body regions of the birds were evaluated to determine the animal welfare level in the groups. The plumage quality was assessed by scoring as good (score 0), moderate (score 1), and poor (score 2), whereas the keel bone deviation was evaluated as present or absent. In addition to the animal welfare parameters, egg production, egg weight, and mortality were monitored in the groups throughout the study. There were significant differences in initial body weight and breast condition values of the birds raised in different three bodyweight groups (P<0.001, P<0.001) and significant differences between the groups in terms of breast width in breast condition groups (p<0.001). It was found to be significantly important the effect of live body weight on the mean egg-laying performance (P<0.005). The initial and end-of trial prevalence of keel bone deviation was found to be over 50% in all groups. The initial total and average feather quality was significantly affected by the bodyweight of the birds (P<0.009). In contrast, there was no significant effect of body weight and breast condition on end-of trial plumage quality. In all groups, total and average feather scores increased with the age, and the plumage quality of the chickens in the groups worsened. It has been determined that the best plumage quality among body regions is in the thigh/cloaca region. As a result, it was observed that the keel bone deviation was observed in approximately half of the laying hens, and the plumage quality worsened with age in birds housed in the conventional cage system.