Oh no! So much sad news! I'm so sorry....
Probably red poultry mites. Ivermectin should treat them. You'll need to empty the coop of bedding and clean the heck out of it. Most recommend burning the bedding, but you can double bag it. You can spray down the coop with permethrin - esp in cracks, under roosts, any crevices. You will have to treat monthly for a few months.
Mites can cause anemia and can kill chickens if you have a bad infestation, and it sounds like you might.
Probably red poultry mites. Ivermectin should treat them. You'll need to empty the coop of bedding and clean the heck out of it. Most recommend burning the bedding, but you can double bag it. You can spray down the coop with permethrin - esp in cracks, under roosts, any crevices. You will have to treat monthly for a few months.
Mites can cause anemia and can kill chickens if you have a bad infestation, and it sounds like you might.