WALTON, Kansas (Reuters) - The first clue is a sign "Fresh Eggs for Sale" in front of the school. There is a sheep pen on the baseball field and the sounds of farm animals greet pupils every morning.
This is not your ordinary elementary school. It is the Walton Rural Life Center, a kindergarten-through-fourth grade charter school in rural Kansas that uses agriculture to teach students about math, science, economics - and responsibility.
The farm theme is so popular that the center has a waiting list to enroll and has given the town of Walton, population 235, a boost, said Mayor Evan Johnson.
"It's been a priority for us and a source of pride," Johnson said.
Students take turns each week feeding chickens, sheep, pigs and cattle. They wash and sell the eggs, make yarn from sheep wool and raise pigs for market - with pork coming back to the school for meals. They also raise vegetables for school snacks.
"The kids love it, and they are learning," said Principal Natise Vogt, pointing to better test scores as one example.
At a time when many small towns struggle to keep their schools open due to shrinking enrollment, Walton is turning students away for lack of space. In 2007, enrollment dipped to around 100, putting the school at risk of closing, Vogt said. But the school has 168 students today.
About half the students come from outside the school's enrollment boundaries and some live outside the school district, which is based five miles away, in Newton, Kansas.
"The parents like the unique curriculum, the project-based learning," said Jennifer Sauerwein, co-president of the school's Parent-Teacher Association. "The kids get that real-life hands-on, day-to-day connection to learning."
Working with animals, for example, is a study in math because students count out eggs in dozens, add and subtract money earned and spent, measure animal food in fractions of each container and equate perimeter lengths with animal pens.
Feeding the animals is not just a chore, said Walton teacher Amanda Paulus.
"It gives them a lot of responsibility in that they are actually caring for something that depends on them," Paulus said.
The first 20 minutes of the school day is spent tending to the animals. About 16 students do the work each morning on a rotating schedule while the rest take a walk outdoors to prepare their minds and bodies for the day, Vogt said. On weekends, teachers take turns going to the school to feed the animals.
Walton students also learn about recycling, composting and reducing waste. One class went through the school trash for five days and discovered that too much of it consisted of paper towels. So, now there is a sign above every dispenser urging students to use only two paper towels.
A wind turbine generates power for the school's greenhouse.
"The kids become more interested in science and the environment and the planet Earth and what we can do to make this a better place," said second grade teacher Staci Schill.
The Walton school's success drew the attention of the U.S. Department of Education, which produced an eight-minute online video about the school, helping to draw visitors from around the country, Vogt said.
Walton Rural Life Center is one of 17 charter schools in Kansas and one of only two elementary schools that is ag-based, the other being a small kindergarten through eighth grade school in Oswego, Kansas.
A charter school gets autonomy from certain school district rules so that it can pursue unique courses of study while still having to meet state education standards. An advisory board monitors the charter school's performance.
Since Walton became a charter school, its test scores have risen, Vogt said. For three years straight, 100 percent of students have tested at proficient or above in state assessment tests, she said.
One measure of the school's success is how the students fare after advancing to other schools in fifth grade, Vogt said.
"The teachers tell us they can always tell Walton kids because they are respectful and know what they need to know, so we feel we are doing our job," Vogt said.
The kindergarten wait list for next year has 35 students, but Walton has room for only 20, Vogt said.
Set up as alternatives to traditional public schools, charter schools typically operate under private management and often boast small class sizes, innovative teaching styles or a particular academic focus. But while they are operated privately, they are publicly funded.
Nationally, the number of charter schools has more than tripled since 1999 and stood at 5,618 in the 2011-12 academic year, according to the National Alliance for Public Charter Schools. They represent 5.8 percent of all public schools.
Only 15 percent of all charter schools in the United States are classified as rural, but the numbers are growing faster than for urban schools, according to the alliance.
Their record of student achievement is mixed, with some - such as the Kansas farm school - boasting good test scores while others do no better than public schools or worse, according to national studies.
To accommodate more students, the Walton school has added classrooms over the past four years ago and is trying to raise $300,000 to build two more rooms by next fall. So far, it has only raised $65,000. A longer-term ambition is to expand the school to eighth grade, paid for with a bond issue to build a larger school.
Reporting by Kevin Murphy; Editing by Greg McCune and Gunna Dickson