How old is the pullet and how long have you had them? Have you checked the vent area for any blood or evidence of pecking? Get Corid and consider worming them because coccidiosis and worms can both cause blood in droppings. Corid dosage is 2 tsp of the liquid or 1.5 tsp of the powder per gallon of water for 5-7 days. Change is daily and make it the only water they have. Treat all of the birds or at least the new ones, and it won’t hurt them. Valbazen is very good for worming. Shake it well. Dosage is 0.08 ml per pound or 0.5 ml for a 4-6 pound chicken given orally. Repeat it in 10 days. A 1 ml syringe without a needle may be obtained free at most pharmacies. Valbazen is found online and in some feed stores. SafeGuard liquid goat wormer or horse paste may be more available. Dosage is 0.25 ml per pound given orally for 5 straight days. Shake it well.