Smothering In Commercial Free-Range Laying Hens: A Preliminary Investigation
Bright, A.; Johnson, E.A., VETERINARY RECORD, 168:512 Published Online First: 9 May 2011
Smothering in poultry is when birds mass together, often on top of each other, resulting in death from suffocation. Smothering is reported anecdotally as a major and unpredictable problem within the loose-housed egg laying industry. In this preliminary study, we carried out an investigation into the incidence of smothering and possible causal factors with commercial free range laying hen producers from The Lakes Free Range Egg Company Ltd (hereinafter The Lakes) and Noble Foods Ltd (hereinafter Noble).
Ten producers and one pullet rearer from The Lakes and one producer and technical manager from Noble were visited between April and July 2010, to discuss smothering incidence, and potential causes. The complete production and mortality records from transfer to end of lay were collected and collated from 10 flocks on two Noble farms. During our discussions with producers, it became clear that there are three different categories of smother:
Panic – Occurs at any stage during rear or lay and is usually a one off event with high mortality.
Nest Box – Most common when hens are coming into lay and one hen visits/uses a nest box, stimulating other hens to crowd into the same next box.
Creeping/Recurring – The most problematic type of smother for producers because once started it recurs throughout lay, although usually with a smaller (1-10) number of birds at each incident than Panic or Nest Box smothers.
The three categories of smothers are not mutually exclusive and although producers recorded smother mortalities they did not report what category of smother it was. In four of the flocks, smothers were responsible for > 40 % of mortalities and a corresponding significant reduction in egg production (Table 1).