That is a good question about waiting for Chopper before feeding Ryleigh.
Perhaps you can take some time and work with Chopper alone, without Ryleigh outside. Because I have a similar issue with Zoee and Taggart. Zoee could care less that I'm calling her whereas Taggart comes running as soon as he hears the door open. But since Taggart is in training right now I have to find time without Zoee around to work on his training.
I'm curious to hear what the more experienced trainers have to say.