Don't know where you live or how many birds you have. I do know that sometimes is not the coop thats smells but the run. I know there are times when it gets wet you can smell chicken poop. If you can put up a fence and grow some flowery vines on it. Annuals are good and you really don't have to do alot of work. Just pick something like Scarlet runner beans, nothing that will hurt you chickens. If you have a run plant some near it. Plant them back from the run and run some string over to it and up about two feet, where the birds can't get to it. Runner beans have pretty red and white flowers and should cover the side of the run nearest his property. You can plant the every year. I have Lilacs planted on one side of my run.