Yesterday was the first day I witnessed my cockerel (RIR) successfully mount one of my my pullets (a BR). I saw it happen again this morning (the same BR), when I let them out to free range. They are all a little over 19 weeks old, 1 of them (a BR) has been squatting consistently, the other three (BR, BR and RIR), more or less have been. They already have big red combs and wattles, lots of red around the ears. No egg song yet, and they haven't had a spike in vocality lately. Any other signs I should look out for? When do you think they will start laying? Who will lay first?