Anytime the weather (i.e. barometric pressure) changes it usually means that more babies will be born. I am not sure why, but it is a common phenomenon in the livestock world. This morning my Dad went out at 4:30 am and checked on the ewes, as it is lambing season. He came back into the house to get the rest of us (my Mom, my sister, and I) because a set of twins had been born, outside again, even though they have a nice shed. We got them moved to a warm, dry pen and the lambs have received their colostrum!