Alternative housing systems have mixed impacts on health and welfare of laying hens.

As Canadian egg farmers are transitioning from conventional cages to alternative housing systems, it is important to evaluate the impact of these on the health and welfare of laying hens. A total of 11 commercial enriched colonies (EC) and 11 commercial aviaries (A) houses from Quebec, Canada, were visited monthly between 19 and 35 weeks of age then every 10 weeks until 65 weeks of age. Each visit, 12 birds were randomly selected to be individually examined and scored for health and welfare indicators either visually (footpad dermatitis (FPD), feather damage and feather cleanliness) or by palpation (keel bone deviation (KBD) keel bone fracture (KBF), wing fracture, laying status and body condition) to determine the impact of housing and age on these parameters. Hens housed in A had a significantly higher predicted probability of KBF (P = 0.038) and FPD (P = 0.016). Although no difference was observed in the predicted probabilities of overall feather damage between housing systems (P = 0.82), the predicted probabilities of feather damage in the cloacal region was higher for birds housed in EC (P = 0.017). Other measured parameters were not influenced by housing types when all ages were combined. Significant increases for predicted probability compared to the baseline age for keel deviation (P < 0.004), damaged feather coverage (P < 0.0001), feather uncleanliness (P < 0.003) and laying status (laying or not) (P < 0.0001) were observed for both systems. Surprisingly, no difference for KBF overtime was observed for either housing system (P > 0.03, non-significant after the alpha-level adjustment). Higher predicted probability in A for FPD compared to the baseline was observed for all-time points assessed (P < 0.0001). Overall, A negatively affected the predicted probabilities of KBF and FPD. Development overtime of most health and welfare indicators should be taken into consideration when extending the laying production cycle.