I have tried to help on another thread, and recommended vitamins for chicks or vitamin B complex. But she has said that she doesn’t know if they are getting vitamins or not because someone else feeds them and waters.
I would try vitamins that contain B2 riboflavin. Also make sure they are getting mostly chick grower or starter feed as 90% of their feed. Chicks who have leg problems may respond to vitamins. Others may have splay leg or tendon issues, but picture of them standing would help.