If you had a petting zoo/ponies at your party

what did you do in case it rained?

I am thinking of having a petting zoo for DS' birthday but am worried about rain. The company I'm looking at won't charge for a rain cancellation but then what do I do about the party - cancel, have a rain date, keep party but without the zoo which was the "entertainment"?

I don't plan on having a tent. I'm trying to keep this party on some kind of a budget