BIT OF BACKGROUND
I have 4 sheep who are almost two years old. They have lots of room, so are not on top of each other. They have not been put to tup, and I keep them just as pets and to have their fleeces for spinning. Blackjack is amazingly friendly with me, Floss is friendly but not overly so (she was very small and sickly as a baby, has only recently caught up with the growth of the others). Lola is happy to be petted, but gets a little skittish and Misty is very timid, and only comes for cheek rubs when I am on the opposite side of the fence. They were all orphaned and bottle fed.
They play with each other and do butt occasionally, or when they are running to get to me. They play with my dog, and butted him once.
THE PROBLEM
Today the butting looked sinister, and was between Floss and Blackjack. Floss had blood on her head. Her head was not cut, and I could not find any wounds on Blackjack. It was mostly started by the Floss, and she kept backing up and running at Blackjack, and backing her into the corner of their penned area. They only stopped when I went into the field with them, and almost got between them. When I watched from the window lola was helping Floss to ram Blackjack. Misty went off to another part of the field for the whole time. I'm concerned that Blackjack is not safe - should I separate them, or is this normal?