This situation can be caused by a variety of conditions like when the does become excited by an environmental change or when the nutritional status (usually water) is restricted.
Eating young often occurs when varmints, household pets, rodents, or some other unusual visitor enters the rabbitry soon after the doe has delivered her young. The eating of young is an instinctive survival response of the doe. Restrict all animals and visitors from entering or roaming near the rabbitry. The problems often occur at night when rodents and varmints are more active.
Other concerns include a check of the water supply system to assure that adequate amounts of fresh, cool water are available and use vitamin/electrolyte supplements in the drinking water during hot periods. Adding electrolytes (salts) increases water consumption. If water is not flushed frequently from overhead water pipes during hot weather, the water may become too hot for drinking. The does may not drink enough water and cannibalism may result. All hot water in these pipes should be flushed at mid-afternoon.