I have a lot of chickens so everyone wants to hen peck something they can dominate with just three I think your adults would be likely to have a good hierarchy so a few chicks should fine, a momma might stand up for them, ours fluff out their tales. Lift their wings for the babies to scoot under if being bullied, I very much doubt - fingers crossed - that a small set will cause too much harm plus the broody one is less likely to pick on the chicks as she is on her bum, just make sure you put food near her so she does not want to push the chicks around to get her fair share, and you may need water closer by but your Wilkie managed fine so it sounds like you are on the right track, look for special chick food for chickens it deals with parasitical gut issues, best of luck dont be tight with the photographs