Well, I think an easier method would be to use a special treat can, something like a little pail perhaps, that makes noise when you shake it with treats in it. (Like BOSS, for example.)
They'll get used to coming to YOU when you shake it. If you're in the run, they'll come into the run and you can give them their treats and lock them up, then go on your errand. Or into their coop, if you prefer.
Mine got so used to coming to the run gate when they saw me come out the back door, because I'd always announce, loudly, "Chickens! I have CHICKENS!" So, now, when they are out of the run, free ranging in the back yard, all I have to do is say, "Chickens! I have CHICKENS!" and they come from all directions. I step into the run and give them treats for their good behavior. Then I close it up and go on my errand.