Unflappable: Wing flapping of aviary-housed laying hens following spatial restriction

Commercial housing systems are becoming more complex to accommodate positive hen behaviors, including wing flapping (WF). Hens need substantial three-dimensional space to flap their wings, and system configurations can influence this behavior. This study examined the timing and frequency of WF among 4 laying hen strains (2 white-feathered and 2 brown-feathered; 576 hens/strain) housed in a commercial-style multi-tiered aviary. Hens were separated by strain into 16 tiered aviary units within 4 rooms (4 units/room, 1 unit/strain/room). Each unit contained a litter-covered floor and a 3-tiered enclosure containing feed, water, perches, and nests. Doors on the bottom tier opened and closed, determining when hens could access litter. Hens were confined within tiered enclosures from 01:00–11:35 daily, providing ∼8.5 h of litter access before lights turned off at 20:00. Ceiling-mounted cameras in each unit captured hens’ behavior on litter. Observers watched 1 day of video footage when hens were 28 weeks old and recorded every stationary WF event. For analysis, time of day (11:35–20:00) was broken into six 85-min blocks of time (A, B, C, D, E, F). A generalized linear mixed model was used to compare counts of WF among the 4 strains. Main effects were the strain and time; random effects were room and unit location within the room. A Spearman rank correlation test was applied to evaluate the relationship between WF counts and density of the birds on the litter. Overall, brown-feathered hens flapped their wings more than white-feathered hens (P < 0.05). More WF events were counted in the morning (time A) compared to evening (time F) (P < 0.05), suggesting hens’ daily confinement within wire enclosures may have increased their motivation to wing flap once they had room to do so. Overall, WF instances were negatively correlated with birds’ density on the litter (r = -0.205; P < 0.001), and a similar pattern was observed within each strain and in F. No correlation was found between WF counts and hens’ density on the litter when hens first gained access to the litter each day (time A). In conclusion, white and brown strains showed different amounts of WF, and time of day and number of hens on the litter influenced how much WF occurred. However, further research is needed to address the impact of intrinsic and extrinsic factors such as age, motivation, litter stocking density, standard management practices like feed distribution, and daily activity patterns. • White laying hens present different wing flapping patterns from brown ones. • Strains of the same feather color also differ in wing flapping pattern. • Wing flapping behavior is influenced by time of day. • Environmental and management factors can affect wing flapping performance.