Lambing is one of the most important times in the sheep farming year: it sets the productivity for the coming season and is the culmination of the previous months’ work. Ensuring the survival of the lamb crop is essential for achieving good productivity, and the period when lambs are born is the most critical part of achieving this. Although rates of lamb mortality can vary across farms, average figures of 15% lamb losses are consistently reported (Dwyer et al., 2016). Newborn lambs are more likely to die in the first few days of life than at any other time in their life: 50% of pre-weaning mortality occurs on the day of birth and up to 75% occurs in the first three days of life (Dwyer et al., 2016). Events occurring in the first days and hours after birth can also be influential for the lamb’s health and growth until weaning and beyond. Thus, a successful lambing depends on what happens in the first few days of life, but this may have been set by events and decisions taken throughout the ewe’s pregnancy and even before mating and conception.