Machen directs and coordinates Extension educational programs related to livestock production for southwest Texas. He conducts beef cattle, sheep and goat result demonstrations and field trials, and he provides technical assistance in the areas of selection and breeding, nutrition and feeding, wool and mohair preparation and marketing. In addition, Machen has conducted hands-on computer workshops for County Extension Agents, farmers and ranchers, school teachers and county clerical personnel.

He is actively involved in youth education and development by assisting with several county livestock shows and the San Antonio Livestock Exposition, the San Angelo Livestock Show and the Houston Livestock Show and Rodeo.

Professional memberships include the American Society of Animal Science, the American Registry of Professional Animal Scientists and Gamma Sigma Delta.