I have a bunch of chicks that are starting to show nervous system signs (very unsteady/drunk gait) and are going blind. I've thought about aspergillosis, but these chicks are in two different locations. Three of them are in the house and have been since hatch kept on dry bedding. The other seven are outside in a wire bottom cage and are given fresh food and water daily. The oldest ones are a month and a half old. The younger ones are a couple of weeks younger. Two of the ones in the house have been blind in one eye each since shortly after hatch. I assumed it was from complications hatching and dismissed it, but the ones outside just started going blind this weekend. It is only affecting these two groups of chicks (which are related) and none of my free-range ones. None have died yet, but I fear it may be eminent. Any ideas what could be going on?