They look pretty good. Considering they're not covered, you will want to make sure the birds can't roost over the boxes--and that there isn't anywhere the birds can perch over the boxes (such as a ladder, ledge, etc) otherwise they will be full of poop every day.
They'll certainly be better inside a coop. I know my birds would probably skip the box and lay underneath--between the cinder blocks. They prefer dark/safe places, so anyplace that's darker/safer (like the space under) will generally be preferred.