Welcome To BYC
Do you have photos of the poop and worms?
What symptoms do you see?
How old are your pullets?
Afik, there are no contraindications between Corid (Amprolium) and Safeguard (Fenbendazole), so you can treat with both.
For Poultry - Liquid Corid dose is 2 teaspoons or Powdered Corid is 1 1/2 teaspoons per gallon of water given for 5-7 days as the only source of drinking water. Do not add any Extra supplements or vitamins that contain B1(Thiamine) to feed or water during the course of Corid treatment.
Safeguard (Fenbendazole) comes in liquid (Goat Dewormer) or paste (Equine paste).
For either one of these, dosing is by weight and given orally. These do not mix with water.
For Roundworms only, Safeguard dose is 0.23ml per pound of weight given orally once, then repeated in 10 days.
For other worms that poultry can have including Roundworms, but excluding Tapeworms, Safeguard dose is 0.23ml per pound of weight given orally once a day for 5 days in a row. No repeat.
Here's how to give medication orally
https://www.backyardchickens.com/ar...dications-to-all-poultry-and-waterfowl.73335/