We are new to raising chickens and received 5 Silkies and 4 Plymouth Partridges as gifts to get us started. We built one pen and a coop for all of them. We have determined that 4 of the 5 Silkies are roosters and only 1 is a hen and the 4 Plymouths are hens. We are been researching and have found information that too many Roosters in one pen can lead to aggression and fighting. We don't want that to occur and are trying to determine how many is too many.