A good place to check if they have mites is look under the wing, that's were I check as it's nice and warm under there and less feathers so you can see them easier. Younger what's your secret to get your hens laying?? I have about 50 hens and am only getting maybe 5 eggs a day and I light them for an extra 3 hours. As for a dewormer I use Panacur liquid.