This is very true, my first batch of chickens were crazy, especially the rooster. Subsequent generations that were raised with adult birds around are much calmer and less vicious.Cockerels really need an older rooster or hens to keep them in line and teach them manners. Since you have neither they will most likely reek havoc. It's kind of like leaving teenagers unsupervised. Your life, your kids, and your pullets lives will be much less stressful if you rehome all of these cockerels or make them a grow-out pen. After all your pullets are older and laying then see about getting a rooster (if you want to) or putting one of yours back with them. Don't get me wrong, I love the dynamic our rooster brings to the flock. He is older though, at least 18 months, and even if he wasn't well mannered my Production Reds would keep him in line.