Ok, thanks, you guys! I had my suspicions that he was having confidence issues, especially with my head hen, who is terrifying, lol. I've seen him mount them several times and it looks like he's lining everything up fairly well, and I did trim him around his vent a week or two ago, because he seemed to be getting a bit too fluffy, but the girls look fine so I left theirs. There is one girl in particular that he gives most of his attention to, so I really expected to have quite a few fertile eggs from her, but she's only had a couple fertile ones so far and the others haven't had any. It's definitely not a nutritional thing, because I've been supplementing with foods that are high in all the necessary vitamins, namely calcium and vitamin d, but there's several others I've been focusing on. I'm pretty sure it's mostly the daylight issue, so hopefully his fertility will be increasing soon. Guess I'll just have to keep an eye on it for a bit. Thanks for the advice, though!
You might remove his favorite for a few days so he can pay attention to some of the other hens. Roosters can develop favorites. One other thing I have run across is hens refuse to let the male mate them. If there is a more willing female in there he will go to her instead. If he isn't a pushy, persistent type, even if left alone and she isn't willing, it may not happen. I've had to change males once or twice over the years because of picky females.