Over the years, she has helped foal a few horses, and on nights when she's waiting for a mare to give birth, she is too alert to sleep. Short, shallow naps are the best she can hope for.

She has been ministering to horses for 28 years, 19 at her present location, a former dairy farm in Toughkenamon, Chester County, a few miles west of Kennett Square. Hers is truly a full-time job - 24 hours a day, seven days a week. She can't remember when she last took a real vacation.

"An afternoon off would be like a vacation," says Roberts, 44, without a trace of regret or self-pity. "One thing with horses: They can't do it themselves. Someone has to take care of them. People send us their horses because they trust us."

Roberts is in the business of providing equine TLC. She runs a halfway house and rehab center for four-legged athletes who are sick, injured or recovering from surgery - show horses, jumpers, racehorses and Western steeds bred for cattle-driving and rodeos.

"When you consider what these horses do and how much they weigh, like any athlete, it's going to catch up with them," Roberts says.

About two-thirds of her patients - "lay-ups" in the lingo of the horse trade - are lame; they have leg or hoof injuries that are hampering their gait and preventing them from performing. Others are suffering from colic or respiratory ailments such as pneumonia. Some are healing from cuts and wounds, others from operations at the nearby New Bolton Center, the University of Pennsylvania's esteemed veterinary hospital for large animals.

Roberts cares for at least 100 different horses a year. About 15 to 20 horses reside at her 15-acre farm at any one time, their owners paying $20 to $30 a day. Some may stay for a day, others for as long as six months. They board in one of 18 stalls, in a place so immaculate that, in the words of one client, "you could eat off the barn floor." A half dozen horses have retired at the farm. Their owners pay Roberts a monthly fee to keep them in the equivalent of an assisted-living facility.

"They eat, sleep and roll around in the mud," Roberts says. To an aged horse, apparently, this is bliss.

Many of the younger horses are restless adolescents and high-strung divas, and the aim is to keep them confined and settled to promote recuperation. They spend most of the time in their stalls, a safe, quiet, stress-free place where they can't run, buck and get into mischief.

Their round-the-clock, private-duty nurse, tutored by experience, is Roberts. She feeds the horses their special meals (sometimes as frequently as six times a day). She gives them their shots and medications. She bandages their wounds and changes their dressings. She massages their joints and muscles and guides them through their exercises and physical therapy. Some horses she walks by hand every day. Others are walked by machine in a circular corral with revolving compartments that nudge them along like active passengers on a merry-go-round.

Roberts needn't state the obvious: She loves what she does. Chronically cheerful, she is endowed with only one gear: overdrive.

"She's got the most amazing work ethic," says Midge Leitch, a large-animal veterinarian with whom Roberts has worked closely over the years. "Her dedication and endurance are remarkable, because the work is grueling, difficult, endless and dangerous. You're dealing with athletes who were at the top of their game. Suddenly they're locked in a stall and feeling either overenergetic or annoyed because of the change in routine. You've got to be careful when you're dealing with 1,100 pounds of locked-up, annoyed, exuberant horseflesh."

One of Roberts' most memorable patients was a polo pony who was hit head-on by a car. The impact split open his chest wide enough to see his heart beating. After emergency surgery, he was sent to Roberts. His condition was precarious at first. "I thought he was never going to get better," she recalls. But she was determined to make him whole. "Every day I could see him healing." After nine months, he was able to leave - healthy, able, with a barely visible scar.

Roberts, who began riding a pony when she was 2, grew up on a neighboring farm, where her father cultivated mushrooms and dabbled with racehorses. As a teen, Roberts helped breed, foal and break racehorses. She trained and galloped them, readying them for races at places like Delaware Park and Penn National. After graduating from Kennett High School at age 16, she made her avocation her vocation, continuing to work with horses, broadening her skills and deepening her experience by apprenticing herself to Leitch.

"I defy you to find a client who doesn't think the world of her," says Leitch, 62, who lives in Cochranville. "The only complaint I've heard is that horses have left too fast," she jokes, referring to horses that recover sooner than expected. "She likes feeding them. They always go home looking sleeker, shinier and a little chunkier than when they arrived, and that's a good thing."

Roberts is a skillful diagnostician, her clients say, who seems to have a sixth sense about what ails a horse and how to speed its recovery. She can tell when a horse is out of sorts, in a grumpy state because of indigestion, or just plain glum from existential angst. She can tell by the way a horse's head bobs whether it's favoring a leg or a hoof, and which exactly it is.

"She is just fantastic with animals," says CarolJean "C.J." Martin, whose lame horse, Woodwork, has been recuperating with Roberts since August. "She can tell every single week how much he has improved. She can feel it in his walk and see it in his eyes. She just knows what's on his mind."

"Horses are sensitive to your mood," Roberts says. "If you're in the barn and in a bad mood, horses will pick up on it immediately."

Is she a horse whisperer, possessed of supernatural ability?

"Omigod, no," laughs Roberts, who is known for her modesty. "It just comes from so many years of working with horses and getting to know them."

"When you work on them and see what they do and how they compete, it's amazing. Horses love to work. The good ones really enjoy what they're doing. They want to be out there doing their thing, and I try to help them get better so they can do it sooner."