When I got him four weeks ago, he was very possessive over the older, very passive mare (she's 12) as she was in heat. Ears pinned, snaking his head and keeping her away from everyone else. That passed and everyone adjusted and life was good.
I was out to the barn Sunday and he was fabulous. I show up last night, he came to me in the pasture, walked him out, and he turned into a monster. He was pushy, anxious, and nearly out of control. Any correction I made, his reaction was 10x what it would normally be. One flick of the lead rope (flat halter, no chains, no knotted rope halter) and he was flying backwards, crazy in his eyes. I fed him in a stall, he would take one bite, pace, turn circles, paw at the door, until he was ready for the next bite. I was not tolerating his clear lack of respect, but any correction I had to make was so minor on my part with major exaggerated responses from him.
I spent about an hour with him, grooming when he's stand still, and decided to put him back. On the way back to the pasture, we got about 50 feet away and he totally relaxed - head down, breathing normal, licking and chewing. When I turned him loose, we stood and watched for about 20 minutes.
He was pinning his ears and snaking his head at all the horses, herding them from one end of the pasture to the other, and clearly trying to seperate the mare of choice from the rest.
I talked to the BO about moving him to another herd with different horses. Do you think this is the best to try to move him away from these gals, or should I not worry to much about him becoming a monster during one mare's cycle?