The owners of Guzoo are waiting for a necropsy to find out how two wolves died but suspect they were poisoned.
Seven wolf pups are now being bottle fed since their parents were found dead in their pens on Tuesday morning.
The private zoo near Three Hills, Alta., has been a battleground between the Gustafson family and animal rights activists for years.
Bill Gustafson, son of zoo owner Lynn Gustafson, says they called their own veterinarian right away.
"From her observation in the pen, and autopsy, she figures it was cyanide poisoning," he said.
He admits it could be anybody but has his suspicions.
"These animal rights groups, I guess people have forgotten over the years, but a lot of them have stated that animals are better dead than owned," said Gustafson.
More tests are being done at the University of Calgary to determine how the wolves died.
Gustafson says they can make the zoo more secure but still doubts they can make Guzoo completely foolproof against intruders.