I did a little bit of everything! I started out trying the apple cider vinegar in his water, but he didn't want anything to do with that. He wouldn't drink his water after I pulled that trick on him, so I squirted as much as I could of an epsom salt flush in his mouth with a medicine dropper. I also had some antifungal (Ketoconazole) left over from an infection a cat had on her foot. So, I gave him a dose of that (1/4 pill) each day--he's on day 4 now. Not sure if that was the best choice, but I had to try to help him!. He also got some plain yogurt, which he ate like crazy one day, and hasn't touched it since. He's been reintroduced to his chicken feed, oats, and cracked corn. When I let him out for a little walk around the house, he raids the cat food bowl too. Since he's been inside he doesn't have as much trouble walking either. I think the cold weather is hard on him, and it hasn't even been as cold as usual here.
Thanks for showing you care for Mr. Myrtle. He's my little baby boy...well, old man after 8 years I guess!