Ok, I know the normal gestation period for a mare. Ideally, my foal will be born the beginning of June. Last night, I was looking at her past foaling records and saw the last baby she had, she only carried it 321 days. I don't know on the others. If a mare has an early baby once, is she likely to have them on the early side again or is it more enviromental factors that play in? If she plans to go this early, I need to start preparing!