Sorry about that! This week has been insanely busy.
I called the police department two days in a row, who just patched me through to animal control. I contacted PETA (put my feelings about them aside!), and they actually did a great job hounding AC for me as well. The county animal control came out maybe Tuesday morning, and told me EVEN THOUGH all his water was frozen, and his hooves are terribly overgrown, they couldn't do anything. So I dug up the landlord's number and gave that to them.
The wind chill up here's been pretty bad, so I haven't seen him out. Today it was almost 30 F (spring is here! Ha.), and I saw him while I was setting out a round bale for my ponies. He looked pretty rough, no blanket, still skinny. So, for now, I'll keep an eye on him, and if it gets worse, I'll start another round of calls...