I looked up the feed and it is not nutritionally adequate for even adult ducks. On their website this is a direct copy and paste of their ingredients along with the nutritional analysis:
“
Ingredients: Barley, whole oats, sorghum, kibbled maize, high protein pellets (soya bean meal, peas, broll, vegetable oil).
Typical analysis: Protein: 11.4%, fat: 3.4%, fibre: 6.7%, calcium: 0.59%, reactive lys mg/100mg: 0.54%”
I would not even feed this to my adult ducks. The protein alone is not even close to being adequate and there is nowhere near enough niacin for a duckling or an adult duck. Not to mention the lack of other nutrients. The only thing that feed would be good for is if it was being used as an occasional treat.
https://shop.topflite.co.nz/products/lucky-duck-duck-food?variant=8661164818484