That could be. I imagine they won't eat until they burst. They probably need the nutrients. Especially since they obviously didn't have the right diet before. Have you ever used Brewers yeast mixed in their food for niacin. And peas are high in niacin as well. I bet after a few days or a couple weeks they will start to regulate their eating a little better.
I dont understand these ducks. They eat like they are never going to eat again. This confuses me. My runners never have acted this way. Is it because they are farm ducks and just another duck in the flock where they had to fight for ever bit of food with 100's of others and they have that mind set here with there new family? They eat and eat and eat till there lower neckline looks like breast. Then they eat more. I have to feed in different places so my runners can eat. Any ideas on this woul be much appreciated.