Extreme crowding in laying hens during a recurrent smothering outbreak

Background: Piling, a behaviour where hens crowd together, is referred to as smothering if mortalities result. Smothering considerable concern for the egg industry, yet vastly understudied. Methods: During an outbreak of recurrent smothering, continuous video footage captured commercial, free-range flock over 35 days. We describe piling observed and potential associations with productivity health indicators. Results: Forty-eight piles were filmed, maximum density 187.93 birds/m2 up 1204 birds in one pile. Piling occurred same house location on 33 34 observation days, first evidence regularity behaviour. Despite extreme bird densities, we did not find between extremity but water:feed ratio temperature range. Conclusion: This study describes most level reported literature offers new insights into this problem its consequences.