Suggestions for coop run design with existing coop

[Amusingpet]

Are there roosts in that coop?

There is one roost in the second level about 5' long. I could enclosed the 3rd level, put in little ladder and another roost in the potential penthouse.

I am starting to get the feeling that this coop will work as a starter but I am going to need a bigger coop.

 

[RobertaD1]

With 10 chicken, yes, you will need a bigger coop.

 

[CinnaBun]

Ideally, you would double the size of the coop, so 5x8' or bigger. Your coop is nice and tall, so consider converting it to a walk-in coop so that you can clean it easier. Look at photos of roost bars, poop boards, etc.

If you want to use the coop as-is for the winter, I would enclose the bottom section in hardware cloth, adding a predator apron and animal proof latch to close coop up at night. Maybe you can put water and food in this area.
The middle section needs another roost bar. I think you can fit another one in there (I think minimum spacing is 12" from wall and other roosts?) Also enclose the space with siding, plywood or wood fencing.
The top, add hardware cloth and leave open for ventilation. I wouldn't make it into a penthouse.