Gestation is only 30 days for rabbits. Litter size ranges from 4 to 10. Methods for determining pregnancy include abdominal development and manual palpation. The abdomen of the rabbit does not generally enlarge until 3 weeks after the mating, which is almost delivery time. Manual feeling of the abdomen is the best determination. Embryos grow into the placental stage around 7 days. Manual examining can be accurate as early as 10 days, however prior to 14 days, it is almost impossible for a lay person to feel babies. To examine the rabbit, place on table and gently squeeze and feel the lower part of the abdomen. It will be soft, an indication of the fluid filled amniotic sac. Babies feel about the size of an olive and you should be able to feel a group of olives or grapes. Delivery occurs usually 29-31 days after mating. Rabbits will dig and make a nest out of their hair and hay. Mom will feed the babies once or twice a day during the wee hours of the morning when most people are asleep. In the wild, when people discover a litter that has been hidden, they assume the litter has been abandoned. However, mom covered them up & left so as not to attract predators. She returns when she is not likely to be observed. Leave a nest alone if you discover one.