I got 5 chicks on September 16th. They stayed in my den in their brooder until about Thanksgiving, when they were moved to their awesome new coop and run in the back yard. I change my furnace filters regularly. However, on Dec. 18th, the thing started blowing cold air. I had a guy come out to look at it; he said the filter was clogged (I had just changed it) and to NOT use the special allergen-preventing filters as they are very hard on the system. He said use regular filters (as long as they are white, not "blue" fiberglass) and change them every 30 days. So yesterday, my furnace had problems again. It was making hot air, but not blowing much of it. I called again, a different guy came out. He said my filter was dirty and that was what was causing the problem. It does look kind of dirty, but not awful. He checked the coils, which were clean, let it run a few cycles, and replaced the filter again. He said the filter was covered with "white dust". This sounds suspiciously like the dust that was on everything when the baby chicks were in their brooder indoors. However, they've been out of the house since November, and I immediately changed the filter and gave everything a good dusting/wet wipedown when they moved out. My question: has anyone else ever had this issue AFTER the chicks were out of the house? The furnace tech guy said it can take some time to filter through the system, but 2 filters in a month? The furnace unit has never had any issues like this before since I got it in 2009. Anyone else have brooder chicks that caused dust/filter issues in your HVAC? Thoughts? Thanks!