I have a 3 YO heifer, this will be her first calf. She is swelled up on her lady parts, her bag is huge and her nipples are hard, but not like they have milk in them. The calf is moving, and other than being uncomfortable, mom is eating and doing cow stuff. I don't know when she was bred, the calendar said the girls could start calving after March 16th based on 280 days. So I would not really consider them over due or anything. Noramlly I feel their nipples and they feel empty. These feel harder than that. But her bag is full and hard too. I think she is going to go any time. Are those hard nipples a worry or just peculiar to her...