You're in Houston? There should be a feed store somewhere that's open, specifically, a Tractor Supply. They don't close for anything, it seems.
Failing that, I usually cook a big pot of rice and oatmeal, raid the fridge fror leftovers, raid the freezer for veggies, etc. Just don't add anything with a lot of salt or sugar. Pull all the dandelions in the yard, too! Cook all the extra eggs, shells and all, plenty of protein and calcium there.
Cat or dog chow blended up with whole grain or a loaf of bread will work. They eat cat and dog food like it's candy. Probably not the best thing for your birds but it's not going to hurt them in the short term.