I just had to add 2 ducks to my flock of 4 cause I ended up having 2 drakes. So now I have a total of six ducks. Appleyards/Cayugas/ Welsh. Right now my duck house that they get locked up in at night is 5x4. Is that enough room or should I add on?
My answer is no......
I have six Ducks and they are locked in an extra large Dog house each night...It still has lots of room for them to move around.
I feed and refresh the water an hour before dark so their crops are full and they do fine till morning.
Your coop is big enough as long as they get out each morning.