You add things besides chicken and rice to that mix, right? If not, that diet is going to be pretty deficient in many things. Here's a home cooking recipe that some of us use for dobies, they're about 80lbs or so. It's a decent amount of work, but it's balanced and proven to do well with sensitive dobe tummies!
Kinetic Doberman Diet
Just make a big batch and freeze once a month. Easy!
The proof is in the pudding, just look at the condition on
her dogs! Doing this for a yorkie would probably be pretty cost efficient too.