Minimal Effects of Rearing Enrichments on Pullet Behaviour and Welfare

SIMPLE SUMMARY: Free-range pullets are often reared indoors, which may make it difficult to adapt to being outside as adult hens. Enrichments during rearing could improve the birds’ behavioural and physical development. Hy-Line Brown(®) chicks (n = 1700) were reared indoors across 16 weeks with 3 enrichment treatments: (1) a standard control; (2) novel objects provided weekly (novelty) or (3) perching structures (structural) provided. All pullets were weighed at 5, 8, 12, and 16 weeks old. Pullets were also tested in two behavioural tests at 9 (n = 87) and 16 (n = 90) weeks of age, assessing fear and responses to stress. At 15 weeks, lymphoid organs were extracted and weighed from 90 pullets. Pullets were transferred to the free-range facility at 16 weeks and housed in 9 identical pens within rearing treatments. Hens perching were counted via video recordings across the first week. Structural hens perched less than the novelty hens in the layer facility (p = 0.02) but there were few other consistent rearing treatment differences. The rearing environments had minimal effects on pullet behaviour and welfare; greater differences may be seen in the adult hens. ABSTRACT: In Australia, free-range pullets are typically reared indoors, which may hinder later adjustment to outdoor access. Rearing enrichments could optimise pullet development. Hy-Line Brown(®) chicks (n = 1700) were reared indoors across 16 weeks with 3 enrichment treatments: (1) a standard control; (2) novel objects (novelty) provided weekly or (3) perching structures (structural) provided. All pullets were weighed at 5, 8, 12, and 16 weeks old. Pullets (n = 87) were tested in a novel arena at 9 weeks and manual restraint (n = 90) at 16 weeks. At 15 weeks, lymphoid organs were extracted and weighed from 90 pullets. Pullets were transferred to the free-range facility at 16 weeks and housed in 9 identical pens within rearing treatments. Hens perching were counted via video recordings across the first week. The structural pullets had the highest relative adrenal weights (p = 0.03) but differences may not have been biologically relevant. Structural hens perched less than the novelty hens in the layer facility (p = 0.02). There were no other consistent rearing treatment differences. The rearing environments had minimal effects on pullet behaviour and welfare, but data from the adult hens did show some longer-term welfare impacts.