I've got a great set of twin heifers that are driving me crazy. The cow has enough milk and is getting extra feed to keep it that way. The calves are "A" and "B". A is always near her mom. lays down inches from her and gets up is mom starts to move away. B always finds a "safe" place to nap in hiding and doesn't always notice when mom walks away. Mom never looks for B as long as A is there to nurse. I have to go find B at least once a day and get her back with mom. Any solutions? I almost to the point of putting dog collars on them and a short leash between!