"And I know people who have adjusted pigs, goats and rodeo bulls," said Giggleman, a professor at Parker University in Dallas, which specializes in chiropractic care.

In Southern California, Dr. Rod Block has tended to an elephant, a paralyzed iguana, a turkey, pigs, llamas and countless dogs and horses.

"You have to be very much in tune with the being of the animal you are working with," said Block, who limits his work these days to house calls throughout Southern California, where he works with several veterinarians.

"A chiropractor promotes the flow of energy within the body. Anywhere there is an obstruction or blockage of energy due to subluxation or a dysfunctional group of muscles, what the chiropractor does is normalize that function," Block said.

Giggleman spends most of his time teaching but still sees patients one day a week. Ninety percent of his patients need chiropractic care and 10 percent need traditional care, he said.