LOL, back in the day when I was stage-managing preschooler Christmas programs, I totally avoided the whole animal-costume thing, because it can go wrong so many different ways. We had Mary, Joseph, the Three Kings, a band of shepherds (boys) in bathrobes and towel-turbans, and a host of angels (girls) in white sheet-surplices and cardboard halos. That way nobody cries because she has to be a sheep when she wanted to be an angel, and nobody's Mom cries because she can't sew a sheep costume.