These "dunnies" are the only restrooms in the entire zoo! However, with 400 animals and only 7 acres this zoo is certainly not very large. The giftshop is arguably a third the size of the restrooms, and the establishment is only open to the public about half the year.
Tautphaus Park Zoo has a more consistent atmosphere and probably a more diverse collection, but Zoo Boise has giraffes and hyenas.