Duck Pen/Coop

[sprky40]

I'm fresh to the duck community and started with two Khaki Campbells a few weeks before Easter and ended up buying two more a few weeks later. I have lost one of them to my daughters dog not too long ago but in need of some help. I'm looking at building a new duck pen for the three K/C's that I have and was thinking of building it 8ft X 8ft with a bedding box area built off to the one side big enough for my two ducks and a few extra spaces for future ducks. Want to know if this would be big enough for what I have and if it will suffice for future family members. I plan on building it with a future run to be built onto it later on but going to also be using an old hot tub as a pond for them by burying it into the ground next to their pen to have it enclosed by the run later on. I have looked at all sorts of plans online but wanted some opinions on my idea. Will this be big enough, they now have our entire back fenced in yard to forage in and usually sleep under my enclosed trailer for now. They tend to take shelter on my back deck as well alot of nights but def ready to start getting them penned up at night and hopefully keep from cleaning up poop everyday off my deck. I'm hoping once this is built to build in an electric door for them to be released out every morning and then lock them in at night. Any ideas would help.
Thank You and look forward to haring others opinions!