WESTLAND, Mich. -- A federal class-action lawsuit has been filed against Petland Inc., accusing the chain of selling unhealthy puppies from puppy mills without consumers' knowledge.

The complaint, filed by the Humane Society of the United States, alleges that the Ohio-based company is the largest supporter of puppy mills.

The lawsuit is based on facts gathered from an eight-month undercover investigation of 17,000 puppies in 22 states -- including Michigan, where the chain has locations in Novi and Westland.

There is a Michigan plaintiff listed in the filed complaint, a woman from Fowlerville. The complaint states the woman said she bought a Boston Terrier from the Petland location in Novi for $999, but found out later that it was sold with a congenital spinal condition.

"They're claiming to be coming from high-quality breeders," said society attorney Aaron Green. "And essentially what they are supplying are dogs that are coming directly from puppy mills, or by way of puppy mills."

Mary McIver represents a local puppy mill awareness group. Her group recently took place in the nationwide protest against Petland locally.

"They're generally not healthy dogs, and the customers don't know this coming in," she said. "And then they're stuck with high vet bills on top of paying a high price for the pet to begin with."

Petland has responded to the suit, calling it a smear campaign and full of false accusations.

"Our puppies receive strict veterinary care and supervision," Petland's Vice President, Joe Watson, said in a statement. "First, each Petland puppy is examined by a licensed veterinarian and provided with a health certificate prior to arriving at our stores."

For more information, visit the Humane Society of the United States' Web site.