Poor coop design?

Put up a tarp that you can roll up or down as needed.

 

A photo might help with ideas but the only things I can think of are to either put an awning or overhang on it or plant bushes or put up a slat fence as a windscreen.

I think the door you are looking for is just for chickens, right. Are you familiar with the guillotine door? it's how you close off a doggy door. I'll try to describe it as I don't have a photo. Cut a hole in the wall near the ground where you want them to go outside and that is big enough for the chickens to get through. Let's say 10" wide for talking purposes. Determine the thickness of the door, say 1/4" thick for example. Put two vertical strips 1/2" thick by 2" wide 1" back from the edges of your hole so they are 12" apart. On top of that put 1" x 3" boards 10" apart. Cut your door 11-3/4" wide. You should have made grooves on the side of your opening to slide the door up and down. Of course, use dimensions that suit the materials you have. And a raccoon can open this door so you need to be able to lock it. Maybe someone can attach a picture.

 

Build a "covered porch" section to avoid rain getting in (unless the rain is coming in @45 degree angle)

 

It sounds as if your coop is similar to this one, but twice as long?



This coop is 7 1/2' wide & 5' deep. We put a covering over the top of the run right next to the coop/shelter and don't have any trouble at all with rain getting into it - yes, we actually do have heavy rains & wind here at times . We used the green, plastic corrugated roofing panels from Lowes (supported by 2 x 4's). Lowes does sell these panels in a much longer length - maybe you could put some of those across yours. You might also try standing up some extra plywood or ....? next to the coop and outside the run to add a little more protection and make it deeper than 4 ft.

Edited to add photo of 2 x 4's supporting panels:

 

Is this the *run* that's getting rained into, or the indoor henhouse?

If it is the house portion, then you need an overhang, or just to enclose that part entirely.

If it is merely the run, and you don't want to put an overhang on, then I would recommend just renovating the run so that it can tolerate getting rain blown in. Wet feet aren't going to kill yer chickens , you just don't want it muddy and smelly in there. Install gutters to direct water off the roof to go well away from the run; dig a small trench around the outside of the run (not right *at* the run walls, tho) to direct surface water away; make sure the run is at or slightly above surrounding grade (you won't be able to fix this til dry season); add some gravel (during the dry season).

For now, temporarily, you could add a buncha wood chips or somehting COARSE like that (NOT shavings, and even straw isn't all that great) to raise the chickens up above mud level. But you will need to remove that before it starts to compost down into More Mud For Next Year.

Regarding the door issue, could you post pics? Then I bet we can make some suggestions

Good luck, have fun,

Pat