Pest control (1)

Rodents and Insects

We have concerns about the likely pest activity at the proposed development, as it is certain that the hen sheds will be very attractive to pests which pose a potential risk to public health.

Rodents

House mice and Brown rats

Both species are commensal, being found in close conjunction with human activity, and it is very likely that the sheds will have problems with one or the other (or both) at some time or another.

House mice are indoor dwellers, and are likely to nest in voids within the building, and feed upon small spillages of feed destined for the hens. They do not need to drink, obtaining sufficient moisture from their food, and require only about three grams of food per day to thrive. As they are essentially an indoor species they will breed successfully throughout the year.

Of the two rodent species likely to become problematic on site, mice are more likely to remain closely associated with the buildings, i.e. indoors, and any health risks they pose will be mainly to the workers. Mice are known carriers of Salmonella spp., which is usually passed on to humans via the hand-to-mouth route, and the link between hen eggs and Salmonellosis is long established.

An article (1) by the University of Minnesota, citing the Centre for Disease control, estimates that one of every 10,000 – 20,000 eggs has Salmonella spp.. Putting this into perspective, this would mean that three to six eggs produced every two days by the unit could contain Salmonella spp., and the presence of mice will increase that number. Although hens can be injected to prevent them from being infected by Salmonella, it is not completely effective and as recently as July 2020, an outbreak of Salmonella poisoning was associated with Lion Brand eggs, from vaccinated hens (2).

Outside the buildings, mice are not likely to cause a significant problem, although it’s probable that Field Mice (a separate species to house mice) will also find the buildings attractive, especially in the colder months, despite being essentially an outdoor–living species.