I have 2 RIR roosters that are about 3-4 months old and just brought home 2 more pullets (18-22 weeks) to add to the flock. They are in separate pens (have been for about a week now) but can see each other and they all roost together in the coop separated by chicken wire. I've let them all mingle a few times and each and every time my two roosters make a bee-line for the new girls jump on thier backs and bite....is this normal and will they continue to do it? This is my first time raising chickens and I know they need to get the pecking order down but it seems so violent.....any advice?