Nope! There are several (now retired) vets/vet techs in the family so I've always taken their advice on feeding my ducks. They actually advised against feeding layer because they said layer feed was created by farmers to increase egg production and that ducks weren't designed to be on added calcium 24/7 which is why so many have reproductive issues (they said their reproductive systems get put into overdrive with the excess calcium).
They instead advised to create an environment as much like their natural habitat would be with calcium offered on the side and as much foraging as possible. I have hens from 3 years and under currently and breeds are Hookbill's, Rouens, Mallards and a runner. I also never had any health issues with my flock besides some minor bumble due to our last place being flooding during a hurricane which washed up a bunch of glass and metal (guy who lived there before us was a belligerent littering drunk according to the neighbors)

. We have moved since thank goodness, but other than that minor bumble it has been pretty uneventful here. I don't know if it's for everyone to feed the way I do, but so far it has worked beautifully for me!