Things I would try:
1) Up their protein. Find the highest protein feed you can or add treats that are high in protein. BOSS (black oil sunflower seeds) are a good protein booster, a bit on the pricey side. You can get them cheaper by using the kind sold in the wild bird feed section of feedstores.
2) If possible, gather eggs several times a day for a week or so. If you have an egg eating predator this should confirm whether you are losing eggs to one. Here, snakes are bad about it.
3) Check for mites again. Best way I've found to definitely confirm mites is to arm yourself with a good flashlight and go in the coop at night. Select a hen and check her closely around her vent, under her wings and under her neck feathers; repeat with another hen. The mites could be black, red or white.
4) Worm them! Use a broad spectrum wormer, not that Wazine stuff which I personally feel is about useless. Don't use Ivermectin to worm while they are in a molt, as it is believed by some to cause feather deformities when used during a molt. My personal preference is Valbazen (albendazole).
Something is going on with your hens, but I get the feeling it's not their fault.
By the way, it's not all that unusual for a rooster not to attempt mating during molts. Roosters can sense when a hen is incapable of producing offspring and normally won't waste his time with a molting, non-laying hen. This is also why you will typically see more back damage in hens that are your best layers. Roosters know which ones are the best, don't ask me how.