At what age do roosters start getting mean? Will they all get mean or does it just depend on the individual? We have 2 roosters that are 6 months old. For the longest time it was just the 2 of them and they are friendly enough. When we added the hens everyone said they would get mean. Now the hens have only been around a few weeks, but so far they're still nice. They come up and cuddle with you and let you pet them.