Sorry about the dilemma with your toddler. I have a tried-and-true baked chicken recipe that might be adaptable to the crock-pot. You could, perhaps, tailor-make it to your needs. The recipe calls for leg/thigh portions but I see no reason you can't sub breasts.
In a nutshell, in a large casserole, pour 1/2 stick of melted butter or margarine, layer 1 1/2 cups of uncooked rice, place what would amount to a whole cut-up chicken on top of the rice and butter, sprinkle a package of dry onion soup over, then pour 3 cups of water over all. Season with additional salt, if you find it necessary. Cover tightly with foil and bake in a preheated 300F oven for 2 hours.
In your case, you might want to eliminate the soup mix and sub some other mild seasoning, along with a bit of salt. The end result is tender, juicy chicken with nicely-cooked and flavored rice.
Here are some tips and a chart
to help you convert this recipe or any others you might want to try in your crock-pot.
Hope this helps.