and have started on a pen that is roughly 14 by 12 that will include a dog house and a 50 gallon stock tank for water for them. Do you think this is enough space? I hope...
It won't get too messy? I mean in general I know that it is going to be muddy and have little grass but will it be ok as in a healthy way for the ducks?
When I started with my first three ducks (two Khaki Campbells & a Pekin), they lived in a 4'x8' pen at night and had access to a run that was approximately 16' by 15' during the day. In one summer, they killed all the vegetation in it by dabbling at everything whenever it rained and generally stomping on everything with their flat feet.
But they are very happy (they have half of the pen/run now) - they always tended to stay in one side of the run, so that's the side that they have divided off for them now, and other ducks have moved into the rest of it.
As long as they have plenty of space to flap around and dry off in the sun after a swim and nest down in the shade for a nap, and have a little bit of mud to make a mess in every now and then, they'll be better off than a good portion of the ducks in the world!