Splay legs is a genetic condition exacerbated by certain on- farm factors. The condition is caused by a failure of certain muscle fibres to mature in sufficient numbers. These weakened muscles are then unable to support the piglet at birth. This can occur in forelimbs, but is more common in the hind limbs.
Certain factors have been shown to increase the incidence of splay leg piglets, namely, large litters, shorter gestation periods, farrowing induction prior to day 113, zearalenone poisoning as well as certain diseases like PRRS.