I had a constant crower I had to process. He crowed day in and day out. He was my only red male, and he was churning out sex links for me. But he had to go. None of my other Roos of any age picked up the habit. 2 weeks ago I culled a six week old who was doing it from his first crow. I think they’re born to crow or not crow.
That being said, remember that’s with ideal conditions. A roo with less than 3-5 females will often constantly crow because he’s looking for more ladies. A roo with too little space will crow. If there are a lot of predators the males often crow a lot. I’ve found that lining the pen with cinder blocks around the outside keeps predators out, and also keeps the birds from seeing all the mundane movements in the yard as constant threats and crowing.
How many ladies does your roo have? How much space do you keep them in? Are there lots of hiding places, and how many birds per square feet?