My ducks are de-wormed at the same time as my chickens. Otherwise, the ducks seem as healthy and disease-resistant as the chickens are disease-prone. Ducks are tough with one exception. Some ducks seem to get foot problems, like bumblefoot.
Our duck eggs are sought by cancer patients. Apparently, duck eggs are alkaline (basic), chicken eggs are acidic. According to our clients, cancer cells don’t thrive in a basic environment, so some cancer patients adjust their body’s environment by eating alkaline foods like duck eggs. We are very careful to discard any eggs laid when the ducks are being wormed or given antibiotics.