The Humane Society of the United States seems to be pushing sows from the frying pan into the fire with its high-profile campaign to ban hog farmers from housing gestating sows in stalls.
French researchers have just found there are more lame sows when they are housed in pens instead of individual stalls.
They say this is a welfare issue and that it’s worse on concrete and slatted floors than in pens bedded with straw.
This is on top of hog farmers' concerns about sows fighting, sometimes quite viscously, when they are grouped in pens.
The fighting usually settles down within a day or two, but there are lingering social pressures with dominant sows hogging the feed, leaving the more docile, timid and weaker ones without enough to eat.
The French findings come from a study of 108 hog farms in western France.
They looked into four main types of group housing adopted since gestation crates were banned in Europe. They are large groups with electronic feeder station in stable or in dynamic groups; small groups in walk-in lock-in stalls, or partial feeding stalls.
They checked sows for claw lesions, scored them for lameness and recorded their breeding characteristics.
Lameness was positively correlated with heel lesions and dewclaw lesions.
Walk-in lock-in stalls were found to be the most protective system.
The larger the group, the more leg problems. Also severely restricting diets increased lameness, especially in the later stages of pregnancy.
Lameness issues increase with the larger number of sows for which each worker is responsible.