Until recently, I had two hens, a pearl and a charcoal. The cock definitely had a preference, and only hung out with the charcoal when the other was nesting. Now that she's hatched her keets, he hasn't so much as glanced at the charcoal, and he's helping the pearl hen raise the keets. In fact, he may have run the other hen off. He treated her pretty badly when breeding season came, and now I haven't seen her for 3 days. My opinion? They pair off at least for the season. I may never know whether it's for life, because if all the keets are pearls, I'll never be able to tell which is which.