It's been a hard winter and a couple of my hens and my rooster are thin despite having constant layer feed, cracked corn, table scraps and scavenging under the bird feeder. They have access to grit and oyster shells too. They have had intermittent diarrhea all winter. My rooster's feathers are starting to break off, not fall out or molt but break off at the downy part. One of my hens is acting lethargic and has a huge crop. All combs and wattles are nice and red, though. There is no blood in their stool. I haven't found any mites, but am wondering about leg mites on 3 of the birds because a few of their leg scales are large and a little peeled up. So, my big question is: What can I use to de-worm them that is broad spectrum, cheap, and easy to get? Will any de-wormers kill mites too? Thank you for any help!