If you haven't already you should start giving a treat call. Some people use words, others a can of rocks, a whistle, anyhting. Just make the same noise over and over while they eat their treats so they associate that word with yummy food.
Eventually they will all coming running as fast as their little legs will carry them when they hear it! Then you can just make the noise before you serve treats.
My girls are reliable most of the time, but occasionally someone will try out a tree to sleep in one night, I go out just before is dark (normally everyone will be settling in the coop) and if someone is missing a quick "chick chick chickEENNNN!" call brings her running! or I at least some crunching of twigs as she hastily tries to get out of said tree!