I have 2 hens and 3 big chicks, and I just got two hens that are 2 years old. I noticed black bugs on the 2 new hens crown, neck and around the eyes - they are about the size of fleas, but they don't move or jump - I had to pull one off with tweazers. What are these and how do I get rid of them? I saw photos of mites on the web, but these black bugs are bigger than mites. I noticed the bugs about 20 minutes after I brought them home and have quarantined them.