thank you both!
i picked up sulmet at the feed store...they didn't have corvid. unfortunately, they didn't have any other ideas for what to do, either. the only thing he mentioned that i hadn't thought of was maybe pulled tendons from slipping? while their cage bottom is not particularly slippery -- it has pine shavings -- part of it has cardboard underneath. it could be ??
i also saw botulism mentioned as a possibility. the treatment for that would be epsom salts, it seems. can i treat with sulmet AND epsom salts at the same time?
http://www.thepoultrysite.com/publications/6/diseases-of-poultry/220/slipped-tendon-perosis
this is what perosis looks like...dunno if that is the same as what you were describing- treated with vitamins and repostitioning the tendon as you can see in the next link
here you can scroll down to slipped tendon if desired:
https://sites.google.com/a/poultrypedia.com/poultrypedia/poultry-podiatry
Here is info on botulism:
http://www.merckmanuals.com/vet/pou...sickness/overview_of_botulism_in_poultry.html
Sulmet treats only 2 strains of cocci, and Corid (in the cattle section) treats more strains - I think maybe all 9, but if that is all they had that is better than nothing!!

Sorry I still don't know what the problem with your chickies is so I hope something works for them!!