My chickens are 3 months old, and we have ended up with only 1 pullet and 3 cockerels. We plan on getting rid of 2 of them and getting 2 or 3 more pullets from the same guy we got these from. Should we try to get some the same age as these or get some that are already laying? Then how do I go about integrating them? The roos are not crowing yet or being too mean to each other, but I assume I need to get rid of them before adding the new ones.