Caecal microbiota of enriched pullets and free-range hens

Free-range pullets are reared indoors but the adult hens can go outside which is a mismatch that might reduce adaptation in the laying environment. If pullets cannot go outside during their development, enrichments provided inside during the rearing phase may enhance pullet development and adaptations to subsequent free-range housing. Enrichments could have multiple beneficial impacts on bird behaviour and health, including affecting their gut microbiota. Additionally, once adult hens in free-range systems start ranging, they show high individual variation in how often and for how long they choose to range. This variation in ranging may correlate with differences in their gut microbiota. Thus, the aim of this study was to determine how rearing enrichments affect caecal microbiota in pullets (15 weeks of age) and how both rearing enrichment history and subsequent range access variation affect caecal microbiota in adult laying hens (64 weeks of age).