redraider you asked so here goes. The coop need's a re-entry door, higher the better. I have recently discovered that you don't need bob's. I'll put in a photo when I'm done of a bobless one that keep's them in. I'd get a small fishing net to catch pigeon's with in the coop. Your probally going to loose a few trying to get them out the door, they'll fly by you. Get them re-entering befor you start and the one's that get out will come back. I'm guessing from the look's of the coop, your intention was to keep kill bird's only. That's alright but you only get to kill it once! With bird's coming back you can use them over and over. I think to many people are in to big a hurry to kill bird's. As a result the dog's not really ready to be shot over but they start and the next thing thry know, they need more bird's and their out. At that point you have to go out and get more. Easier to keep live bird's that come back. They'll breed and shortly you will have plenty of bird's you have to kill to avoid overcrowding.
I don't really know to much about pigeon's, I just used them a lot and in the process found out some thing's that made life easier for me. Trapping I am absolutely no good at. I went into old buildings and barns at night with a flashlight and picked them. some I netted. I'd get up where the bird's roost and just shine a bright light on them and pick them up by hand. Some fly off on you but most just sit there and let you. I might add, do it in a dark place. If your in a spot where you need to net, get them from behind. I have a long handled smelt net. Just come from behind and when you feel them in the net, turn the handle to wrap the bird in. If you try to net from the front, most the bird's will dodge the net, very frustrating.
I found my old pigeon trap today and it's a masterpiece that never got me one bird. I know they work because I've listened to guy's talk about it. I never figured it out tho. I think you have to be smarter than the bird.
Let's get back to the coop. Once you get the birds settled in good, usually after they nest, just open the top door, on the re-entry trap, and let them come and go on their own for a few day's, don't push them out. Now the bobless re-entry.
This thing is simple to make. All it is is a box. take a 1 x 6 and make the four side's . You might need about 8" wide by 12" high. Next take another 1 x 6 and put it in the middle of the box, top to bottom. On top of the box,inside, is a large landing platform for them to leave on. I think that platform is necessary as it give's them no room and nothing to grab underneath to try and get back out the re-entry slot's. Outside on the bottom, put another 1 x 6 all the way across. On the top of that put another 1 x 6 outside for a landing platform for re-entry. Nail this box to the fence on top of that second cross bar down from the top of the coop.
Now on top of the box just make a 1 x 2 frame to hold the exit door. It could be on hinge's or just silde over the hole. Cut out the chicken wire everywhere.
What is happening here is that the bird's inside are flying to the platform inside which is above the re-entry slot's. At the re-entry slot's on the inside, they have no place to land, it's 5 1/2" in and 5 1/2" up to get out, they can't do it. When they are out, they come back to a door that's closed and land on the platform at the slot level. The slot's there are 3 1/2" wide and about 6 1/2" tall and immediately drop down another 5 1/2" inside. As soon as they go in they are trapped inside, no way back out and no bob's needed. There are bob's on mine, I just discovered I didn't really need them like this.