Well I certainly understand in being limited with what you can feed, I've been in that place myself. You just have to do the best you can. If you can't get a better quality food due to availability, expense, etc., I'd just try supplementing their food with healthy things like chopped veggies or yogurt, or fresh meat if you have the chance. The most important thing of course is that they are fed (even if not the "best" food) and loved .