Thanks to you both! They are not doing any worse, at least, & no other chickens have showed symptoms yet. I'm wondering about enclosing the roost area more--maybe they're getting too cold. I don't know if I've ever seen information on the ideal temperature for chickens--I should look that up! I noticed they roost all scattered out these days so they're not keeping each other warm.
I hope to go to Africa some day...which country would you think is the most interesting? I am interested in both nature & human culture. I would love to see baobobs, the Congo river, the Kalahari desert, anything really old, & a tropical rain forest. I saw some baobobs in a park in Honolulu but they weren't big. The rain forest there is considered sub-tropical. We lived on the Big Island for a year--really fun after the culture shock wore off & we found the cool places to hike. They weren't too big on signage there. Are those ads for volunteer/vacation travel bogus?
You are welcome, but don't worry about chickens and temperatures - they are hardy birds and if they are not huddled together then they are not cold for sure!
Which countries? Gosh thats a hard one. Botswana looks great but be sure to go in your summer months (its blisteringly hot around December time). Congo river - leave that one for national geographic - you really don't want to find yourself in DRC or Congo-Brazzaville cos its not safe (I used to work in northern DRC). Sadly, most places that has rainforest is not the best in terms of security at the moment - no, Rwanda is a good place - gorillas and all that. Baobabs you'll find in lots of countries. South Africa and East Africa (Kenya and Tanzania) are good for national parks - lions etc. and are geared up for tourism, so probably less hassle than other countries.
Dunno if the volunteer / vacation stuff is bogus, but its rubbish - they achieve zilch. Development should be left to local people and professionals to support them.
Hope that helps a little.
All the best