I have a pregnant mare, she is due April 29th.... She sleeps indoors. I'm just wondering, how close to the due date should straw be used as bedding? Her udder is just beginning to fill up... Also, what are some other signs of the pending birth? I know about the loosening of the muscles, but what are some others? My mare is older (she's 17) and this is her first baby, so should I expect an earlier birth? I've heard different opinions about older mares and giving birth... Thanks!