T.J. McPherson and his wife Barbara were among the last large dairy operators in Colleyville, bringing in Holstein cows and creating a modern milking operation with a filtration system. During the dairy farm period, the Rock House was the McPherson family farmhouse. Dairying in the area began to decline in the 1970s as developers sought more land for housing developments, and the opening of Dallas-Fort Worth International Airport in 1974 intensified regional housing demand and accelerated the conversion of farms to subdivisions. As land prices skyrocketed, many farmers sold their properties. After the McPhersons retired in 1987, they sold their land to the City of Colleyville, which turned it into McPherson Park. The Rock House and the renovated Dunn/Tirk log barn remain reminders of the city's dairy history, and plans for the purchased farm included preserving the Rock House and repurposing it as a multi-use educational facility for conservation, green technologies, and other city programming.