I'm not familiar with that food. Is it specific to ducks? Normally when I have ducklings I start them with a "starter" food, then switch to "grower" and then move to an adult feed. It's possible they missed some of the essential nutrients for baby ducklings. I would make sure they both get 1 ml of liquid vitamin B complex over treats or food every day. Then make sure their adult food going forward is for ducks. Purina makes a duck formula. I order Mazuri waterfowl through Chewy.com. When they do begin laying you'll need to provide a bowl of oyster shells on the side. They will eat that when they need the added calcium. Also, so many things can go wrong with ducks, you might want to consider adding a couple more females to your flock as you never want to have a lone duck...that would be devastating to them. And if you end up with one being male, you will need a few more females for the proper mating ratio. You should always have 3-4 females per male.