When my sister-in-law was trying to persuade me to let her keep chickens vicariously, she gave me loads of info on eglus - fox-proof chicken houses. Company which sells them will deliver you the chickens as well, and they run courses and stuff. A bit of an investment, but then it would be worth it if they really are fox-proof, as you'd save in the long-run by not having to get new chickens and do your own repairs on a coop every time one got taken.

Here's the link

http://www.omlet.co.uk/products_services...rvices.php