Until recently, Emily Scherer raised goats in the heart of Denver. They lived in a 33-foot pen on her quarter-acre lot. She used their manure to fertilize vegetable plants whose produce she sold at a stand in her front yard. One goat, she says, produced enough milk for her family of three. Her goats were a special breed: the Nigerian Dwarf, ideal for urban farming. “They’re my favorite animal,” Scherer says. “Goats don’t bark and they can live outside and their manure is actually useful.” Fully grown, a Nigerian Dwarf…