Thank you all so much. After reading your posts and then researching tapeworm and aspergillosis and after searching locally for something to help treat an obviously unknown problem, and feeling powerless... I decided I had to do SOMETHING. So, here's what I did with my limited resources and time:
1. I visited the only feed store w/in a 30 mile radius at 5pm last night. (We had major commitments all day long.) I bought the only wormer that they had in stock at that time (Rooster Booster Triple Something-or-other). I read up on it when I returned home and see that it's got, as everything seems to

, supporters and detractors. But, like I said, I couldn't do nothing. I added it to their feed last night and they're munching happily on it today.
NOTE: I decided to treat all the hens because I figure if one's got something there's a good chance they all do. Also we have another hen who has a strip of feathers missing off her neck, and has had this for a while. Maybe she's just showing different symptoms? Maybe she'll benefit? I figure it will do no harm or at least very little given our circumstances.
2. After reading about all the benefits of garlic, I added this to their water this morning. I did use garlic and apple cider vinegar alternately over the winter when they were spending a lot of time in the coop, but since it's been nice out I have quit doing this. Again, I figured it's not going to hurt and may help out more than I know.
3. They do a little free-ranging in a fenced area during some of the daytime. There are lots of leaves to scratch through and I was thinking this was a good thing. Maybe not? (I'm thinking fungus...?? I do live in an arid area, but we've had a lot of snow melt and rain lately. In the next few days I'll be cleaning up in this yard/area.
Fortunately, I am off all week and will be able to monitor more closely than I have this past week. I'll let you know how things go… If you think of anything else I should be looking for please please let me know. Thanks a ton!