Scores of uniformed students quietly file into a great room cluttered with worn furniture, used books, and a baby's playpen. The place is on the verge of erupting in a din of school's-out chatter, but first there is kneeling and prayer:

"For the sake of his sorrowful passion. Have mercy on us and on the whole world."

This is the afternoon routine for students in kindergarten through high school at St. Philomena Academy in East Fallowfield Township, a cooperative academy of Catholic home-schooling families who join together two days a week to provide a school-day experience for their children.

Families come from the surrounding counties and from Delaware to spend their day on a campus of tiny classrooms and hand-me-down desks. An outdoor recreation area feels more like farm than playground. All of it doubles as the home of the family who started it all.

John and Donna Kurtz founded St. Philomena's when they realized that the challenges they faced in home-schooling their children were shared by other nearby families. But the Kurtzes faced those trials more intensely than most. They have 21 adopted children.

"I'm sure people look at us and say, 'Don't you guys have brain cells?' " said Donna Kurtz, 51. "But this is what we're supposed to be doing."

From a seven-acre home and headquarters, the Kurtzes run the school, a charity, and a family - with the help of a band of volunteers. Their home life and outside activities fall under the rubric of St. Joseph's House, the Kurtzes' foundation. The nonprofit organization accepts donations of food and clothes, which helps provide for the family and also assists an extended group of needy residents in the area.

The couple's staunch Catholic faith and antiabortion views play a major role in efforts, said John Kurtz, 55.

The family started the home-school co-op in 2002. Currently, it has 95 students and an all-volunteer teaching staff of 18. Most of the instructors are parents of children in the school.

Students in grades K-12 attend two days of classes in surroundings that evoke an updated Little House on the Prairie. Students can also return for one day of optional tutoring. Parents, some of whom are certified teachers, share expertise and teaching duties. The remainder of the week, students are home-schooled.

Mary Therese Zirolli, 19, a graduate of St. Philomena, said the school helped prepare her for life after the academy and avoid being stereotyped as a home-schooled student.

People say, "You actually talk and socialize, and you don't dress funny?" said Zirolli, who was one of seven in her graduating class at St. Philomena.

St. Philomena's "gave me a foundation for me to become who I was in a safe and comfortable environment," said Zirolli, now a sophomore at Immaculata University.

The academy uses the curriculum of the Mother of Divine Grace School, an accredited long-distance learning program in Ojai, Calif. The curriculum is a classical liberal-arts program designed by Laura Berquist, a pioneer in home-schooling and Christian education.

St. Philomena's is an example of the variety in configurations of home-schooling co-ops, said Carol Topp, author of Homeschool Co-ops: How to Start Them, Run Them and Not Burn Out. They can be as small as two families or involve hundreds of children, Topp said. With its curriculum and class structure, St. Philomena's is a member of the National Association of Private Catholic and Independent Schools.

At the academy, named after the saint proclaimed "Patroness of the Children of Mary," students attend classes in a small school building that is a labyrinth of tiny rooms with worn desks and blackboards, and bookcases filled with used books.

The Kurtz family lives in a house next door, but the first floor there is also used for classes. The hallways are crowded with cubbyholes filled with backpacks. Donna Kurtz teaches math in the family kitchen while her husband teaches 9th grade nearby.

The Kurtzes married in 1984 and first settled in Havertown. They tried to have their own children, but were unsuccessful. They did not want to undergo in vitro fertilization, so instead, "they found a way to have peace," Donna Kurtz said.

Peace came by way of Rosa, then Natalie, David, Maria Elena, Mari Carmen, Martha, Sandra, Maggie, Alex, Jonathan, Galina, Peter, Dominic Joseph, Dominic Anthony, Martin, Michael, Jose, and Joseph, Aura, Erni and Nicholas.

Many of the children came with backgrounds of neglect and abuse. The Kurtzes have adopted 18 of the children and are guardians of three. They range in age from 1 to 28.

All but one lives at home. Some teach in the school. Some work and attend Delaware County Community College. One will start studying for the priesthood in the fall.

Over the years, the family has moved several times and given up jobs to tend and educate the children. Donna Kurtz worked as a teacher, John Kurtz as a contractor. They lived temporarily in a church basement in Bolivar, Pa., and then in an empty convent in Southwest Philadelphia, at the invitation of clergy.

They landed in East Fallowfield in 2001, when Alexandra Bennett, of Unionville, offered to sell them her property at a drastically reduced price of $130,000, partly because she was moved by the family's situation.

The St. Joseph's House foundation takes in about $200,000 a year from donations, fund-raising, and government subsidies to care for some of their children who have special needs, said Chris Galligan, a CPA and St. Joseph's House board member whose children attend the academy. Most of the funds help operate the school, which is tuition-free, but many parents make donations to keep it going. The Kurtzes do not receive a salary.

With a strained economy, times are tougher, but tough is nothing new to a family with 21 children.

"If we based our lives on finances and thinking about what we could humanly do," Donna Kurtz said, "then we'd just have three kids and still live in Havertown."