Is it ok for my ducklings to eat flies

[Miss Lydia]

My drake ate a salamander last week and only because it was right in front of him. lol
I'd rather they not eat them, I like having them around.

 

[Luv Ducks]

Mine love to catch flies and can do it really well. Even the Mule ducks do a good job of it. I have heard of farmers getting them to help with fly control around their livestock. Mine would do a good job for them.