It's a Roundworm.
You can use Safeguard Liquid Goat dewormer or Valbazen.
To treat Roundworms Only - Safeguard dose is 0.23ml per pound of weight given orally once, then repeated in 10 days.
To treat most worms that poultry can have except for Tapeworm - Safeguard dose is 0.23ml per pound of...