In a barn on his 400-acre ranch south of Pueblo, Colo., Hersh Saunders sharpens a long blunt-end knife called a halaf.  A blue crocheted kippah, a Jewish skullcap, covers the bearded rabbi's silver hair. Outside the barn, sheep graze and chickens peck near a small synagogue and rows of organic vegetables.

Saunders has spent the last 27 years working as a prosthodontist, fitting people with dentures, crowns and bridges. But these days, you're just as likely to find him breaking ice in livestock troughs on cold winter mornings, or using a skid-steer to mix manure into his huge compost pile.

Sliding the knife across a whetstone, Saunders explains that nicks can't mar this blade. He's a shochet, a kosher slaughterer who follows ancient Jewish law. When he takes an animal's life, the cut must be clean and swift.

"I don't hate these animals," he says. "I like them a lot, and if someone was going to kill me, I'd want it to be really, really fast and painless."

The Brooklyn, N.Y., neighborhood where Saunders grew up was a kosher world. "All food was specially taken care of," he says. "It was blessed and (handled and processed) according to the laws, imprecations and warnings in the Torah." For observant Jews, keeping kosher makes eating into a religious act.

There are different theories about the intent behind kosher law's technical prescriptions. But like most Jews, Saunders, who continued keeping kosher as an adult, assumed kosher certification meant that food was produced with high ethical standards. So several years ago, he and his wife, Rabbi Elisheva Brenner, were among the legions of Jews who were horrified to learn of cattle being flayed alive, and of undocumented and underage employees working in dangerous conditions at large kosher meatpacking plants.  The biblical injunctions weren't written to address industrialized meat production; no one could have anticipated that animals would be trucked from crowded feedlots to huge slaughterhouses where they might be shackled, dragged and hoisted into the air before being killed.

"Our response to that was we're not going to eat meat at all," Saunders says. "And we didn't until we were sure that the animals were treated correctly and that they are handled right at slaughter." The couple couldn't find local kosher meat from humanely raised animals that weren't pumped full of hormones. So Saunders decided to start producing it himself.

He spent two years training to be a shochet, and studied with renowned animal scientist Temple Grandin to learn her techniques for humane slaughter. Saunders and Brenner then started their own herd of Barbados blackbelly sheep, a resilient heirloom breed suitable for raising on grass, without antibiotics and hormones.

When his blade is ready, Saunders enters a lamb's stall and speaks to it quietly. Keeping the animal calm is critical, he says,  as is keeping himself focused. "We are going to move from a sensate creature to dinner," he says. "We want to do that in a way that preserves the honor and the energetics of the entire system. Otherwise, it's just some kind of lust."

He hugs the animal between his knees, recites a Hebrew prayer and slits its throat, spilling the blood into a black rubber pan.  The lamb dies quickly, but Saunders doesn't hurry. He holds the animal for a few minutes -- enough time, he believes, for its soul to leave its body.

He immediately skins and prepares the lamb for kosher inspection and butchering. It's meticulous work, but Saunders proved a quick study: His knowledge of human anatomy and surgical training transferred easily to performing the required examination of the animal's internal organs to ensure they are free of blemishes and disease, and to removing the nerves, veins and fats that are forbidden by kosher law. Finally, he rinses and salts the meat to remove blood, and sprinkles salt on the hide, which will be shipped out and made into parchment for holy Jewish scrolls.

Earlier this year, Saunders and Brenner started processing and selling their meat. And they refitted a slaughterhouse in Fort Collins to allow expanded production. It will handle their own animals, and others raised according to their standards. Thanks to online sales, they already have customers as far away as Michigan and Alaska. And it turns out that it's not just Jews -- they've heard from Christians and Muslims, too. "I love that because it bridges things and brings people closer together," Saunders says.

On a personal level, he says, ranching has deepened his understanding of Judaism. He even tends his herd on Shabbos, the Sabbath, when Jews are forbidden to work. "(I've) discovered a connection to my ancestors, who cared for their animals on Shabbos. They even named their children Leah, (which means) cow, and Rachel, ewe."