Can a rooster fertilize eggs if he is young but crowing? I'm not quite sure how old this young roo is. I was thinking 5 months old? He is crowing and one of my girls started laying and I put him in with her today he pretends to try and breed her but I dont think he knows what he is doing. Will it take him long to figure it out? With him being so young how long should I wait to see if he is producing fertlized eggs with my hen?