I was also going to ask if it could possibly be a call duckling. Although, 4 days makes a big difference in the life of a duckling. Do you have any pics of the other 3 at the age that the younger one is now? It may just simply be the difference in growth, those first few weeks, they change so drastically.
@Pyxis are Welsh Harlequins usually sexable at hatch? Bill color? I forgot.
@Pyxis are Welsh Harlequins usually sexable at hatch? Bill color? I forgot.