Get your poo at the zoo. The Detroit Zoo will be handing out buckets of animal poop for free to one-thousand visitors at its upcoming Greenfest, an annual celebration for Earth Day. The five gallon bucket of what's being dubbed "Detroit Zoo Poo" is actually a nutrient rich compost processed at the zoo's anaerobic digester. Each year, the processor converts tons of animal waste into gas that helps power the zoo's animal hospital and the fertilizer is a byproduct of that process. The event takes place on April 14th.