If the chicken wire is in good shape, you can attach it to the wood using 3/4" Poultry Staples. You can find them at any home center, Home Depo, Lowes, etc... I think you can make this into a nice little coop. Just take your time and plug all the holes. If you have power close by, you can put an electric fence/hot wire on the structure. That will solve a lot of predator problems. You can find what you need for that at your local farm store, and I am sure they will help you with advice about installing it. It is not difficult. It looks like all your door needs is a cross brace to bring it back into square. If you add the partial piece of plywood you can do the same thing. Try and make it fun.