Well, I haven't wormed any of my birds ever and they free range. However, after worming, do throw out the next 10 days or so of eggs. One way to confirm the type of worms to make sure you are giving the right drug for the right type is to take a fecal sample to the vet and ask for a "fecal float" test for worms/paracites. Because if it's not worms, it could also be a form of cocci that doesn't cause bloody stools.