Without trying to be mean, I’m just gonna state the obvious….if you knew you were going to have chicks hatching, why wouldn’t you have what they need on hand and ready for them? I ask for a simple reason - we’re better able to help you find a different solution if we know why. It’s kind of pointless to tell you to change them to a certain food if you can’t find it.

Is chick starter not available in your area? I know we went to
TSC yesterday to get dog food and I noticed there wasn’t one bag of chick starter in the whole store!! Not one of any brand. (No chicks, either) They only had 2 bags of All Flock, but then there was 3 pallets of layer food. If that is the issue, then we need to get creative finding a solution.
Layer food isn’t the best for them, but when chicks are out being raised by a broody hen with the rest of the flock, I’m not dumb enough to think those chicks aren’t taking in some layer food out there. So obviously short term or in small amounts, they aren’t in immediate danger from eating it. But if possible, you need to get them changed over. They can have either Starter, Grower or All Flock. I feed my mixed flock of roosters, layers, chicks of all ages, and freeloaders All Flock or Grower. New chicks get one small bag of Starter, and when that’s gone they get what the rest of the flock eats. So you do have options besides Layer.