Evil Fairies Love Hair by Mary G. Thompson
Ali and her middle school classmates are raising flocks of fairies to make their wishes come true. But growing a flock is harder than it sounds: the fairies eat only human hair, and the rules for dealing with them are confusing, misleading, and subject to change. As Ali and her friends struggle to earn their wishes, mistakes are made, spells go awry, and soon Ali is up against hundreds of two-inch-tall imps who have very big plans. Comedy and fantasy intertwine in this lively tale of intrigue, magic, and the power of hair.