Thanks for the comments! I do have comfrey, and extra daylilies they are welcome to chomp on (could get those clumps of ditch lilies back out of the far pile of extra weedy junk) and apple mint. I figured as Bonehead said, plant outside, they could eat the parts that try to grow in, for fun. Like texaskitty, I wondered about trying to grow something right in their pen, brassicas, mustard greens, get it started with a milk crate over it, but thinking, that'd probably not last very long. We'll see- having fun learning.
We'll pay attention to that coop. We are suburban but expect fox, raccoon, and black snake may well visit. They are all seen once in a while already. He did get an electric fence - that was first so he could geek out on the electric part. I am not asking too many questions, I don't want him feeling pressured, he needs to be busy, he is retired and golf is only once a week at best. So if they range the yard, it may change my herb planting plans.
