I have two female Cayuga's. They look healthy, but my friend wants me to improve their diet. Their wings are 'angel winging' as she puts it - meaning the tips of the wings meet or cross. Apparently in birds that means something in their diet isn't being met. All of the threads I'm reading is they feed their ducks what they feed their chickens. I have feed from Tractor Supply, and they rummage from the chicken feed. Crumbles, Bird Seed, Oyster Shell or Egg Shell from Chicken or Duck, mealworms.. Is there something I should be putting in their diet? Are they fine?