great question LL.

I think I would raise the question by using the other animals as a starting off point. Something along the line perhaps of, "What an understanding workplace we have. I have my own stress related condition for which I think having my own therapy animal present would help me. What steps are necessary to apply for this?" This is all that your employer need know. In fact it is more than they need know but I am one to err on the side of basic courtesy.