I just got a new Mini colt, 1.2 yrs. Old and not ready to geld yet (waiting for the other T to drop). My 2 yr.old Mini gelding loves him and they are best buds. My 13 yr. Old Mini mare however is doing the "put the baby/pre-stallion in his place" thing and she is so aggressive toward him, (continually charging, kicking and biting and even kicking the fence repeatedly when he is on the other side of it), that they have to be separated. She did not do this when my 2 yr.old came in as a 10 month old but this new boy is different than Redford was when he came here, he is still very baby-headed, no maturity at all. How long will she do this? Will she only accept him once he is gelded?