A third candidate, Mary Varner, 17, of St. Thomas, Pa., is employed as a milker and calf feeder at a nearby dairy farm.
The changes in the contest rules are a reflection of the changes in the county's dairy industry and in the attitudes of consumers in recent years.
Though Franklin remains the state's second-highest milk-producing county, the number of farms is decreasing.
Consumers' buying habits have turned to low-fat and cholesterol-free foods, a significant factor in the production and marketing of dairy products.
Yet the idea behind crowning a dairy princess annually for the past 30 years remains the same.
The girl who wins the title represents the dairy industry for a year. Her main function is to promote the consumption and sale of dairy products and to improve relations between rural and urban people through one-on-one contact.
Franklin County's first dairy princess was Jean Meyers Koontz, who was crowned in 1967.
"I was honored to be a representative of the dairy industry," she said.
Koontz grew up on her family's dairy farm, milking between 75 and 80 Holstein cows - along with a few of her own Ayrshires - just west of St. Thomas. Her two brothers still operate the farm today.
"I milked cows, I disked the fields ... I did it all," she said.
She also served as president of the county 4-H Council and was junior leader of the 4-H Western Dairy Club.
But Koontz's duties as dairy princess were limited to riding floats in local fair parades and attending a few functions where she would give a five-minute speech.
"The girls today are utilizing more of their gifted abilities in promoting the industry," Koontz said. "I didn't do what they do today."
Outgoing Dairy Princess Christiana Mickey, 17, of Waynesboro, Pa., traveled more than 1,500 miles throughout the county and the state over the last year, spoke to nearly 2,000 schoolchildren and attended countless store promotions, agricultural functions and fairs, just to name a few commitments.
She also wrote newspaper articles and produced radio advertisements, all promoting dairy products.
Thirty years ago, the physical appearance of dairy princess contestants weighed heavily with the judges, a point that remains significant but which has shifted considerably.
During their interviews, the girls are quizzed on their knowledge of the dairy industry, not on whether they like to cook and sew, which was one question asked of Koontz when she ran for the title.
The honor has turned into a job of sorts, one that demands a lot of time, and one that has required the princesses to know what they're talking about.
"There have been a lot of controversial things over the last few years we never, ever encountered before," said Julia Meyers, co-chairman of the dairy princess committee.
Specifically, the girls have been faced with retooling their promotional strategy to fit the needs of today's consumers.
Skim milk, yogurt and cottage cheese have become the dairy products of choice for the everyday consumer, Meyers said.
"We didn't have to worry about cholesterol and fat even 10 years ago," Meyers said. "It was not an issue."
Dairy princesses have been confronted by animal rights activists, and they had to contend with the controversy over bovine somatotropin (BST), a growth hormone used by some dairy farmers to increase milk production.
But for people whose families have earned their living through agriculture, and who are confessed "milk-a-holics," like the three girls running for this year's title, promoting the dairy industry is a labor of love.
"People don't realize how much work goes into farming," Schoenberg said. "The dairy industry has been knocked down a lot, but dairy products are good for you. They're not all fat and calories."
Educating youth about the benefits of drinking milk is what Varner wants to focus on.
"We need to get more young people to think of milk as a good thing and get them to drink more of it," she said.
Tonight's dairy princess pageant starts at 7 p.m. at The Lighthouse Restaurant, Chambersburg.