After a trauma my girls who where laying nicely started laying shell-less eggs and laying outside. It took a few weeks. Give them extra protein while they are regrowing their feathers and in time they should straighten out. They are lucky to have someone who is taking such good care of them.
I would say that is just what they have gotten used to and you are probably right that they didn't have a roost before. You could try putting them on the roost at night to show them. Once they try it they might like it. When mine were several weeks old I started putting a small roost only an...