Lillian Loraine Stiles was riding on a lawn mower in her front yard Saturday when she was confronted by the dogs, described as pit bull-rottweiler mixed breeds, said Milam County Sheriff Charlie West.
Investigators think Stiles was attacked when she got off the mower and headed into her house shortly after 4 p.m.
Stiles had severe bites over her entire body, and a man who tried to help her was bitten on one leg, authorities said.
The dogs were found at the home of Stiles' neighbor, Jose Hernandez. Five of the dogs were in custody; a sixth was shot dead by Stiles' husband.
Jack Stiles was inside watching a college football game at the time, he told the Austin American-Statesman.
"I couldn't keep her off the lawn mower. She loved it. She was proud of her yard," he said.
Weldon Smith and his wife were driving by the Stiles home when they spotted the body. He told the paper the dogs, each 70 to 90 pounds, acted like a wolf pack.
"I saw it, and I didn't believe it," he said. "It's like something out of a horror movie."
When the dogs came at him, Smith ran for his truck.
The sheriff's department will send the findings of its investigation to the Milam County District Attorney's Office, which will decide if any criminal charges will be filed against Hernandez.
Thorndale is located about 70 miles west of College Station.