You have fairly small dogs who wouldn't need large meals. I suggest Eagle-Pack! It is excellent quality. Apparently, the best diet and least costly is homemade...which most of us lack time for, but people swear by it. Here is the contact info for a woman who has researched this topic for many years:
peremi@earthlink.net She is filled with facts you might be interested in. Avoid IAMS- they actually experiment on dogs!! For non homemade that isn't THE most costly, go with Eagle-Pack. My dogs love it! If that lady doesn't reply, go online to 'homemade dog foods' you will find tons of ways to do it.