Those are roundworms. Get some Safeguard (Liquid goat wormer or horse paste) or Valbazen (labeled for cattle) to treat those. Safeguard is fenbendazole, and is often not recommended during molt as it has the
possibility of causing feather issues, I have personally never seen any issues, but the possibility is there. The Valbazen is albendazole and is fine during molt, you will likely have to order the Valbazen on line, the Safeguard is usually available locally. The red in the second picture is intestinal shed, probably from the irritation from the worms. Safeguard dose is 0.23 ml per pound of body weight, and repeat dose in 10 days. You can use an inexpensive digital scale to get a weight. Use an oral syringe to dose orally. The Valbazen dose is 0.5 ml for a standard sized bird and repeat dose in 10 days (actual math for Valbazen dose is "weight in lbs / 2.2 x 20 mg / 113.6"). Roundworm is very common, and very easy to pick up in the environment, you may need to worm regularly to keep your birds healthy, the eggs live a very long time in the soil. Make sure you do the second dose at 10 days, the medications kill the worms, but not the eggs, the second dose is necessary to kill any eggs that hatch after the first dose, to stop the cycle. You may see dead or dying worms in dropping after worming, or you may not. Sometimes they are expelled, but many times they are just digested. I would worm all your birds, they have all been exposed. Lock them in the coop at night, go out early the next morning before light, take them off the roosts one at a time and dose, turn them out into the run. When the coop is empty you've gotten them all. For any that don't like being held, wrap them in a towel like a burrito to hold the wings. Shake the medication well, it settles out, draw up your dose, pull down on the wattles and put the medication at the front of the beak no more than 0.5 ml at a time, and release the wattles and let them swallow. Repeat until the entire dose is given. That will reduce the chance of them aspirating any medication. The meds are very safe, always round up to the next easily measured mark when you have a fraction, never round down. Under dosing can lead to resistant parasites.
Tractor supply stores usually have 3 ml syringes, you can get 1 ml oral syringes at many pharmacies, just ask. I order them in bulk on Amazon.
Alternately, this is how to safely administer oral medications:
https://www.backyardchickens.com/ar...dications-to-all-poultry-and-waterfowl.73335/