These little things have showed up in my pigeon coop in the last 2 weeks. I’ve cleaned out the run and replaced it with new dirt and they just came back. They cling to the feeders and the waterers. They don’t bother the birds, I just want to get rid of them. I’ve tried mixing some sevin dust and poultry dust into the dirt. I’ve sprayed them with neem oil. How can I get rid of them and what are they?