Nice build and great that you are thinking ahead in that you may need it as a hospital, quarantine area, or to integrate new chickens into the flock.
My one suggestion is that you cover the floor with linoleum or something like that to make clean up easier.
Speaking of clean up, how easy is it to change the litter in there? Do you have to empty it through the top?
Thinking ahead of future uses is a very practical idea. It's been built to accommodate adult birds as well as chicks. The platform for feed with the assistance of a brick for the little ones is well placed to avoid much wasted space.
