Quite a lot, but it isn't everything. There are always outliers when it comes to the individual disposition of a rooster that is of any breed, but breed does matter. If you have a breed that is known for aggression or gameness, you might find it is a lot to deal with, especially if you are just a backyard chicken keeper. However, it is also possible to get a rude awakening if you have a rooster from a breed that is known to be good-natured and gentle only for him to turn out to be a total hellion.