A few weeks ago, we got two new lamancha goats that I'm assuming we're infected with mites. They've got bumps on their ears and faces and have had some hair loss, especially down their backs. It is spreading rapidly to the other goats. We've used pour-on Ivermectin. The majority of our goats just suddenly had bumps on their ears and faces like the first two and some goats' eyes appear to be sealed shut. We would like to know what is causing all of this and how to stop it.