The PO Ranch was established by the brothers Milton and Hammond Pollard of Pueblo County, Colorado, from whose name the brand was derived. Having known Charles Goodnight in Pueblo, the Pollards wanted to raise cattle in the recently opened Panhandle. In 1878 they drove the first PO herd to the Canadian valley and located their headquarters on Elk Creek, between the divide of the Canadian and Washita rivers and about six miles east of the site of present Canadian in Hemphill County. William Young, who had an interest in the stock, was the first foreman of the ranch. William H. Hopkins and Edward H. Brainard were also among the cowboys who helped drive the herd from Colorado. About 1879 the English immigrant Robert Moody, who had known the Pollards in Pueblo, joined them at the ranch. Two years later he bought out Milton Pollard's share and was in business with Hammond Pollard for a year. In 1882 Hammond sold out his interest to J. B. Andrews, a merchant from Pueblo. By then the PO Ranch controlled a fifteen-square-mile spread east and south of the Canadian townsite. On the ranch approximately 6,000 head of cattle grazed. The PO cattle were driven annually over the Rath Trail to Dodge City for shipment to Kansas City, and supplies were freighted to the ranch from there and Mobeetie, thirty miles to the south. In 1884 the Moody-Andrews Land and Cattle Company began leasing neighboring sections.
The Big Die-up of 1886-a year of drought, cold, and low market demand for beef in which thousands of cattle died on the plains-prompted Andrews to sell out his interest, leaving Moody in undisputed possession of the PO. As sole owner, Moody began drilling water wells, an operation often hindered by quicksand. However, the service he rendered the PO enabled it to survive new land laws, a decline in cattle prices, and the elements. When the Panhandle and Santa Fe Railway built through in 1887, Moody moved his headquarters to Red Deer Creek southeast of Canadian. Taking advantage of new state legislation making railroad and school land available for purchase, Moody bought 15,000 acres south of the Canadian River for seventy-five cents an acre. He joined other ranchers in erecting windmills on his range so that even the farthest pastures would have water. With one of his sons, Thomas, Moody formed the Robert Moody and Son Cattle Company. Additions in various parts of Hemphill County brought the PO holdings to more than 100 sections. Thomas T. McGee, who had bought out Will Young's interest, served as foreman; he later became sheriff of Hemphill County and was killed in the line of duty at Canadian in 1894. Under Moody's leadership the PO, from 1885 to 1895, saw a period of transformation from open range and line riders to fenced pastures, blooded Herefords, and systematic business methods. Even so, the ranch declined in size and importance after the elder Moody turned it over to his heirs and moved, first to Kansas City in 1900 and later to Long Beach, California. Over the succeeding years, particularly after Moody's death in 1915, the PO Ranch was sold piecemeal to farmers and smaller ranchers.