How much space does a bantam need?

Will your pen be movable, like one of those tractor coops? If you can't allow your chickens to free-range, then the next-best thing would be to move the pen so you chickens have access to fresh greens & bugs. They will eat a small area clean to the dirt.Then it could become a stinky pen. Obviously, I'm a free-ranging nut! LOL!

I have bantams, and I use the same space rules of thumb as you read for the standard size birds: 4 sq. feet per bird indoors, plus 10 sq. feet per bird outdoors. Bantams are smaller than standards, true, but they also can be quite active (mine sure are). I think about it this way: I'll never be sorry about building a pen too big, only too small. Build bigger, if you possibly can.

Oh, that's difficult. If you don't mind my asking, what is the restriction? You just don't have more space?

Maybe if you made a very persuasive case to your father, and demonstrated your seriousness about this project by, say, offering to do extra chores around the house, he might be convinced to let you have a bigger pen.  Good luck!

Is it that he says "3 1/2 X 4" or that he says "this location" (which only has that much space)?  Bantams need less space in general than largefowl, but d'uccles are pretty active birds.

Does that space include their coop area?  How tall can you make you pen and coop?  It is possible to make a multi-level coop or pen that increases the floor space--if you have sufficient height.