PA
I don't know anything about chickens, except eating them. However a thought just came to mind.

Couldn't you make a sort of cradle sling for it, that is above ground level, that allows the legs to dangle, but supports the body, but also allows for the chickens bum to be free so it drops it below so it isn't sitting in it.

A wierd idea maybe, but if the bird isn't able to sdtand and walk, then why can't you do that, but make it such that it is really comfortable.

Am I mad :-)