Yes, very easily mites when it's this cold. They attach themselves to the chickens and keep warm and reproduce on the birds. They have a nice warm host as shelter and nice warm blood to eat. A lot of people think that as the weather gets cold, the mites go away. Not so.
pour on Ivermectin works very well. put a drop on nape of neck. A product that we have used with great success is Bronco. It's actually a horse product. Once spray under each wing and one spray on the vent area.
Glencoe, Ontario here.
This was our first year with laying hens and it went well except we aren't set up for the winter so we butchered them when the weather got below freezing and we were breaking water several times a day.
Our project for this winter is to get better set up to have a few more birds and to be able to keep them over winter.
It has been very cold here in southern Ontario. Our chickens are still laying well and they don't seem to mind as they wandering out several times a day. I have a heat lamp in their coop though so it helps a bit I think. How do I know if I have mites? I haven't seen anything on them. They have a bit of matting on their backs that I assume is moulting. There are no bare patches. I use wood ashes in their run and sprinkle diatomaceous earth each week when I add new bedding. Also, does anyone worm their chickens routinely? Have read both sides and looking for advice. First year with chickens.