They might be too young still ... I remember having to do a lot of chasing around at dusk last summer until the chickens matured and starting going in on their own. Also, are there a couple of roosting beams in the coop?
Perhaps try hemp instead of pine shavings? Allegedly, it's a "Less dusty alternative to typical animal bedding options! Faster composting, superior odor and ammonia control. More Renewable. Less acidic." We're using this currently, but only for the past couple of weeks, so I can't say whether it...
