MileHiRocky,
Do a search of my name and read my posts concerning runny bm's and feeding. I learned a lot, but at the cost of a few hairs and many bags of food. One of the most important problems was switching to soo many foods too soon. It will take them a while to get adjusted to a food. A healthy dog will not starve. So, if they aren't eating at all I would take them to a vet ASAP. Take a stool sample and rule out any parasites that could be causing the problem. Two. Try adding an enzyme to help digestion. Yogurt, Prozyme etc. Prior to switching foods, try going to bland diet of chicken and rice until their stomach settles. Then slowly add in the kibble over a course of at least a week, if not longer, as in our case. And three, cut back their food during winter months or periods with reduced activity. Overfeeding will cause diarrhea too. Feed them not by the guide on the bag, but on how they look. Feel the spine, ribs and hips.