Lambing is the process of a ewe delivering lambs, about 147 days after mating. Lambing occurs ideally at a lambing site that the ewe has chosen in the preceding days. Labour generally begins between 4 and 12 hours before the lambs are born. The ewe will variably display discomfort just prior to lambing, especially young sheep. Once third stage labour has begun the lambs are usually born within 2 hours with the ewe standing or lying on her side. Lambs are born in a sac which breaks during the lambing process. Lambs can be successfully born either with the front legs first or the back legs first. If the lambs are not too big they can be born with a front leg back, or both back legs retained.

If the lambs have difficulty being born, or are slow to be born, their survival is at risk. This risk is minimized by ensuring that ewes are not too fat at lambing, that ewes have a good frame size, and ensuring that the ewes are fed adequately so as to prevent metabolic diseases.

If a ewe is having difficulty in delivering lambs, assistance can be given. This requires that the birth canal is explored if the lamb is not obvious. If there is a mal presentation, it can be gently corrected. If the lamb is too big, gentle traction can be applied by pulling on the legs. At all times the hands must be kept clean, and lubricant should be used. Assisted ewes should be given an antibiotic injection.