Lehigh County Humane Society shelter manager Cary Moran says necropsies conducted Monday show that at least one animal was shot and the others might have been trapped.
A state game commission website says fox hunting is legal in Pennsylvania from October through February.
Animal welfare officials had initially feared the animals were puppies. But Moran says their eye sockets and teeth more closely resemble foxes.
DNA tests are under way to confirm their species.
A woman walking her dog found the bodies Friday in woods near a park in Lower Macungie Township, outside Allentown, the Lehigh County Humane Society said. The bodies were in or near a bag that had been torn open, perhaps by an animal.
The discovery came the same week another animal was found skinned, with its feet cut off and rope tied to one leg, about 20 miles away in Lynn Township. That involved a larger animal, perhaps one sought for its pelt, according to humane society Officer Christine Wiggins. Two pairs of thin latex gloves were found beside the animal and will be sent to a forensics lab.
If it proves to be a coyote, the case may amount to little more than a citation for improper disposal, since it's legal to hunt coyotes in Pennsylvania. But investigators thought legitimate hunters would have disposed of the body properly.
Coyotes are now more common in Pennsylvania than black bear or bobcats, according to state game officials. The Pennsylvania Game Commission now allows them to be hunted and trapped to reduce their population. More than 43,000 coyotes were bagged in 2010, according to commission data.