Dog breeder organizations — and some feline allies — are challenging the Agriculture Department's imposition of tougher standards on pet breeders who sell online to remote buyers.

The licensing and inspection standards imposed in 2013 were billed as a crackdown on Internet puppy mills. The Chihuahua Club of America, the American Russell Terrier Club and the Miniature Australian Shepherd Club of America, though, think the rules burden innocent breeders. "The rules are an unjustified regulatory overreach," attorney Philip Herbert Hecht said during a court hearing Thursday.

The new rules regulate "sight unseen" sales, where the buyer and seller are physically separate. The Agriculture Department estimated that the new rules cover 2,600 to 4,600 dog breeders and roughly 325 cat breeders. Skeptics say this underestimates the impact.

The Agriculture Department further estimates that breeders would have to pay several hundred dollars to comply. Skeptics contend the costs could be much higher.