This tractor is heavy, sturdy, and protected enough it can be used year round. My ducks love it, and chickens would too! It was cost effective at only $150 CAD. It only used 4 4'x8' plywood sheets and 5 20' 2"x4" plywood pieces. Screws, staples, hooks, hinges, and latches were the additional supplies I used, along with hardware cloth and chicken wire. I only sustained two injuries!
Here you can see the front is made for pulling. It has hardware cloth on the bottom half and on the top half has 2 layers of chicken wire. The roof is one layer of chicken wire. The chicken wire was stapled every inch and the hardware cloth was every 4 inches, with boards over the edges.
Here you can see the side, the other side is the same but without a door. Hardware cloth all the way up the sides. The door is double latched with latches that require spring-loaded pins to lock them in place.
And here you can sort of see inside. The ramp flips up and acts as a door so the ducks can be shut inside when moving, or at night. There's a shelf inside (1'x4') for food, bedding, supplies, and treats.
The coop was the size it was planned to be. It is 4' by 6'4" and houses 6 ducks at 6 sqft/duck. It will hold, tightly, 8-10 ducks. I did not add nesting boxes because ducks lay wherever they want, a lot of the time. It's 4'6" tall and slants down to 3'3". I do have to crouch but I honestly don't mind it at all!
The run area was unfortunately smaller than I planned for due to a miscalculation. It is adequate, though, as my ducks will be free ranging daily with supervision. There's 6 sqft/duck. If the grass is short, they can go under the coop, which boosts it to 10sqft/duck.