So how do vets regularly spay and neuter wild feral cats? They don't need a gas box for this. There is nothing humane about this method of killing. So, do feral cats feel less pain, or less suffering than domesticated cats? I think not. Some honesty needs to enter the picture here. And that is that the gas box is the cheapest way to kill. Let's state the facts ...these cats are being disposed of. What they think or feel is simply irrelevant. When my vet euthanizes cats she gives them a sedative 20 minutes prior to the actual euthanization. This is the only truely humane way to end lives. And don't we owe them this?