If they are going to be eating various foods other than starter, they will need grit to grind it up in their gizzard.
Make sure they always have plenty of water.
In an emergency situation, for no more than a few days, offer them a selection from each of these categories:
--protein foods (cooked egg, meat, fish, bugs, slugs, snails, etc. Cooked beans or other legumes are also acceptable protein sources, but the animal-based ones tend to be more complete proteins, so I would try to include some of them if at all possible. Cat food or dog food can also be a protein source.)
--calorie sources (bread, grains, birdseed, warm or cold cereal, crackers, cooked potatoes, etc. Try not to use things that are heavily salted, and whole grains are definitely better than refined grains. But in a pinch, just offer them some choices and hope for the best.)
--fruits & vegetables (anything you would eat; also grass, dandelions, or other safe wild plants.) These are a source of vitamins & minerals that may be missing in the other foods, and also fiber.
Try to offer more than one thing from each category, and provide enough that they can pick and choose the ones they want. Yes, this is wasteful, which is an extra reason not to feed this way for long. But it should keep them alive and in reasonably good health for up to a few days. For longer periods of time, it becomes much more important to have the proper balance of nutrients.
