I have a roo that isn't doing his job. He seems to be a 1 woman man. Over the last 9 months I have set eggs from his flock four times and each time only 1 hen is fertile(different ones each time).He has between 8- 12 hens (most are last springs chicks) and no competition. They have 16+ hrs of light, a heated barn, and are laying well so its not the hens. I know fertility goes down in the winter but 2 out of 28 is a bit much.Any ideas how to motivate my roo?