A general rule of thumb is starter crumbles the first two weeks, then switching (I did it slowly) to grower pellets.
At two weeks, I started mixing in grower pellets (ground up a little at first) into the crumbles, at first mostly crumbles, then increasing the relative amount of pellets until the crumbles were gone and they were just eating grower.
I forgot if you are using chick starter. If so, add niacin in the form of capsules dissolved in their water (100 to 150 mg niacin per gallon) or a tablespoon of brewer's yeast on their food in the morning. Niacin supports nervous system growth.
I also gave my ducklings gro-gel once during their first week for a good start.
At two weeks, I started mixing in grower pellets (ground up a little at first) into the crumbles, at first mostly crumbles, then increasing the relative amount of pellets until the crumbles were gone and they were just eating grower.
I forgot if you are using chick starter. If so, add niacin in the form of capsules dissolved in their water (100 to 150 mg niacin per gallon) or a tablespoon of brewer's yeast on their food in the morning. Niacin supports nervous system growth.
I also gave my ducklings gro-gel once during their first week for a good start.