"We have a responsibility to imitate the natural food chain of the animals — in terms of both animal welfare and professional integrity," Aalborg Zoo says.

The Aalborg Zoo in Denmark said it would take certain surplus pets such as chickens, rabbits and guinea pigs to be "gently euthanized" and fed to its captive predators.

A zoo in northern Denmark is asking pet owners to donate their unwanted guinea pigs, rabbits, chickens and even small horses – not to put them on display but to feed them to the zoo’s predators.