Feeding Fido or Fluffy a raw, all-natural cuisine could land you in the slammer for up to six months if you're not careful where you buy the deer, duck or other meat.

The trendy pet diet, called "prey model," in which owners try to feed their pets critters similar to what they'd hunt in the wild, has resulted in a surge in illegal sales of raw wild game online, wildlife investigators say.

People caught selling raw meat without a permit face up to five years in jail and a £5,000 fine. Those buying the illegally obtained game face up to six months in jail and a £500 fine.

In 2010, its first year, The Fish and Wildlife's Internet Crimes Unit logged 177 arrests and 92 warnings for cases involving illegally buying or selling wildlife or raw game meat online, some of it for pets.

Pet owners go on Craigslist and eBay, asking where they can score a squirrel, pheasant, rabbit, goose, duck, chicken, just about any game to feed their cats and dogs. Some seek raw fish, meaty bones and organs such as hearts, livers and kidneys — everything a growing carnivore needs.

"It's happening nationwide," said George Wilson, head of the Internet Crimes Unit. "The philosophy behind it is feeding your pet a hormone-free, naturally grazed diet - saving owners from having to buy expensive surgery and medication, such as glucosamine for dogs, but costing the environment a whole lot more.