I'm trying to teach my 2.5 yo Red Heeler to pull open the screen door to let herself inside. But she doesn't stay interested in tugging games in general when I try to prime her for the action of pulling a rope attached to the door. I've got her to mouth the tugging object for reward, but she won't stay on it very long; and she gets bored with the rope or tug toy pretty quickly when I just try to get her to play with it with me; so she just stops even mouthing it and lays down and looks at me.
Any suggestions? tia