When a tom gets old enough for his head to turn bright blue and red when he struts, is he sexually mature? My BR tom is just getting to that age. I bought a new, unrelated tom for my hens from last summer because I needed new blood in the flock. The tom is a little young. A month ago he still had the barest stragglers of fluffy tips on his feathers behind his head, but he also had a beard started on his chest. I am just hoping he will be able to manage the hens in a month or two. How long after his head goes bright blue when he struts will he be fertile? He has gotten bigger and definitely is taller than the girls now, and is starting to stand up to them and walk toward them when strutting, instead of ducking and moving away like last week.