We are in the midst of building our coop and run. The run will be a 12x40 foot area on an unused side of our house. Now, we happen to care for a handful of strays in addition to two house cats. When we can afford it, we take the strays to the vet for their turn to get fixed/vaccinated/etc. Here's my question. One of our strays is an obvious ex-house cat. He's super friendly, non-aggro... he'll walk by a raccoon without so much as a look. Unfortunately, he's got FIV so even though he's graduated to living in our house, we keep him sequestered in a guest room so he doesn't come in contact with our house cats. Our guest room happens to be on the side of the house with the run... so it would actually be very simple to put a cat door into the window and allow him access to the run (it's got a roof) at his leisure. Is there any issue with this? We don't think he'd bother the chickens, and we'd obviously monitor it at first. FIV isn't transferable to chickens as far as we know, so that shouldn't be an issue. Anything we haven't thought of? The roof of the run will be primarily a heavy bird netting (we have hawks and eagles in the area).