What a sad but wonderful story and Bless you and your husband and his work mates for caring for these little guys and their mom. My DH and I are volunteers with a rescue program here in our area. We usually get the medically fragile kittens that have to be bottle fed every hour or two until they are strog enough to eat on their own. What we are told to feed them is a product that is a mother's milk substitute that is in powdered form that we mix with warm water;. This powder can be purchased in the pet dept. of any Walmart for about $10 . Once the kittens are able to eat on their own we mix MEAT baby food with the milk substitute to make a thicker milk and as the kittens get better at eating we add more babyfood to the milk til its almost pure baby food. Beechnut meat baby food is the best babyfood as they don't have any preservatives but in our area Beechnut brand is hard to find so I buy Gerber chicken, turkey or lamb food. The kittens love it as do our big kitties!!!! Again, thank you for the kindness you are showing to the mamma cat and her kittens.