The effect of genotype and housing type on welfare parameters in EGG chicken

The aim of this study was to investigate the effect of genotype and cage type on egg production and animal welfare in laying hens. The Welfare Quality Protocol for laying hens, other protocols developed for asessing of laying hen welfare and many scientific studies were utilized in this study. Egg yields, dirty and broken egg rates and mortality rates were recorded in the period between the age of onset of egg production and the age of 56 weeks in white and brown laying hens in traditional or enrichable cages. Also in these flocks, clinical evaluations (for the body feather losses as well as the injuries on comb, the abnormalities related to eye, beak, toe and chest bone and lesions on pad of the feets) were conducted to evaluate animal welfare in winter, spring and summer seasons. In the study, it was determined that egg yield, broken and dirty egg rates and mortality rate were significantly affected by the genotype, cage type and genotype x cage type interactions. Compared to white laying hens, egg yield, hair loss in head and neck, foot sole lesions and chest bone abnormalities were found to be higher in brown laying hens. In white laying hens, the rate of dirty and broken eggs, hair loss in the back region, crest injuries, crest abnormality, finger abnormality and beak abnormality were found to be higher. Egg yield, dirty and broken egg rate, mortality rate, hair loss in head and neck area, crank injuries, crank abnormality, finger abnormality and soles of foot soles were found higher in chickens housed in enrichable cage than traditional chickens. Eye, beak and thoracic abnormalities were not affected by cage type. As a result, the results obtained in this study revealed that laying hen genotypes were affected differently from the cage type. It was concluded that health and welfare parameters of chickens were negatively affected in enrichable cages than traditional cages. Keywords: Cage type, egg production, genotype, laying hen welfare, mortality rate