宾夕法尼亚州（美国州名），养鸡场
APRIL 19, 2013
Chicken Farm, Pennsylvania
Photograph by Peter Essick, National Geographic
Chickens provide the fertilizer on this Pennsylvania farm. The mobile coops are relocated daily to distribute manure evenly so that it won’t drain into the Chesapeake Bay.
农场里养鸡，同时也可以给农场的土地施肥。养鸡人会每天挪一挪鸡笼子，使鸡粪均匀地撒到这片土壤上，而又不会让粪肥流入切萨皮克湾(大西洋海湾，伸入美国马里兰州与弗吉尼亚州)。
http://photography.nationalgeogr ... hicken-farm-essick/