It's my understanding that there is not evidence protein is actually what causes angel wing, just a suspicion??Very good info Eggsighted only thing is with them growing so big so fast cutting protein till after 10-12 weeks can also help on angel wing.
On the Purina flock raiser, none of my ducks experienced angel wing and I never fed anything else. But I absolutely am here to learn and KNOW many people have different experience.
