Well, if the chicks are still alive when you find them some feed I would highly recommend that you investigate "fermented feed". Basically put some feed in a bucket, pot, or whatever. Stir in enough water to barely cover the top of the feed . Wait a little while, maybe 30-45 minutes(?), and add enough water to once again cover the very top of the mixture. Stir this mixture up 2-3 times a day and keep it covered with a towel, piece of sheet, etc.,...anything to let air in but keep bugs out. Do this for three days. A white "froth" should form...stir this back into the mixture. Once three days pass scoop some of this out and put in a shallow bowl or on a plate and feed to your chickens. You want this "mash" to be the consistency of oatmeal...not so running it won't keep shape, but not really dry, either. This is called "fermented feed" or "FF" for short.
Some positive aspects of this fermented feed is that it will be much more absorb-able by your chickens and they will get more nutrition from eating it than they would from dry feed. Lots of the nutrition of dry feed is lost in their poop. Keep dry feed available to them, though, as you never want them to go hungry (as you're finding out). Feeding FF twice a day would be great, but once a day is better than none. FF also has lots of probiotics in it and thus will help create a healthy digestive system. Finally, feeding FF often reduces the amount of feed required by 25-50%....definitely a positive thing, especially where feed is hard to come by.
Best wishes,
Ed