Wow......I always wanted to find a redfoot crossing the road too! Sounds like you are doing everything right. Yes, they can do fine in a secure fenced in yard. I assume there are shrubs etc. for shade and security. If you provide that they don't really 'need' a box shelter but they will use one and you will find that they prefer such a site. Don't worry, after a week or so in the yard he will know just where he is.