Thank you! They look a lot like magpies but the one difference as far as I can tell is the black stripe on the beaks of ours. I couldn't find any picture of magpies with that.
I cant find any ducklings that look like these. they dont look exactly like mallards, could they be a cross breed? they were bought at tractor supply about 2 weeks ago. top picture is recent and bottom is when they were younger.