I want to agree with bringing them in, put them in their brooder with pine or paper towels (I use paper towels for bedding. Put in a thermometer and set one side at 90 degrees F. Put in 2 small waterers and a feeder. Give them the medicated chick starter and a clean fresh water and a waterer with probiotics and maybe vitamins and stop giving anything else. Your chicks may be fine. But they've been eating things and around older birds and likely stressed at their new transitions. Don't put them back out until they have their feathers. I worry. I might be in the minority but I keep my birds in 6+ weeks then house separately inside my coop.