Before you buy hardware cloth check out wayfair (free shipping), amazon, and cutler poultry. Either of those buildings would work, but for either of them you need to bury hardware cloth around the perimeter of the building and if you are concerned about predators still trying to get in, extend the hardware cloth up a foot or two on the side of the building. That will take care of anything tunneling into the building. You are soo lucky, it looks like you have enough lumber to do whatever you decide. You can't use an arrow type stapler to secure the hardware cloth, coons will just pull it out.In the long run you will lose less chickens if you make their quarters secure and not even bother trying to kill off predators. Keep an eye on craigslist and your local paper, you should be able to score some chain link for the run reasonable/cheap and chain link will work as long as they aren't in there at night.
