Quote:
Something in spinach reduces the amount of calcium the ingester can absorb. This is particularly important in laying birds, since calcium in needed for eggshells. If not enough calcium is being absorbed, a duck's body will steal it from their bones.
My vet told me this when i brought in my runner with egg binding issues.
A good spinach subsitute is Kale. It has lots of calcium in it, and it's green and leafy.
I guess some spinach is okay as a treat every now and then, probably more so when a female bird is not laying.