Picking on each other already

I've been putting the boys on the floor a lot lately b/c they're trying to crawl. Well it seems like everytime I put them both on the floor, no matter how much space is between them, they end up on top of each other. Yesterday I had to seperate them several times. One of the times they had rolled up next to each other upside down and they both had the foot of the other brother... knawing on it! Sometimes one of them will get sideways and will be kicking the other one in the face! Oh and if Darcy gets down there with them it never fails they pull her hair and she ends up screaming b/c they WILL NOT let go!