Last night (30th April 2013), however, we spotted the rooster mounting one of the hens.
This morning, there were two eggs in the nest but I’ve got no way of knowing whether one of them belonged to that hen or not. I think I’ll keep a note of the number of eggs per day and see what happens.
Rooster sperm apparently stays in the female for up to three weeks so that should hopefully be enough for her clutch of 12 eggs. Fingers crossed he was successful.