* Carbon monoxide gas: Animals are placed in a chamber that is filled with carbon monoxide gas. The gas quickly renders the animals unconscious and then kills them.
* Intravenous injection: Animals are given an injection of a barbiturate or other drug that quickly stops their heart and brain activity.
* Gunshot: Animals are shot in the head with a captive bolt gun or a firearm. This method is only used if the animal is too aggressive or dangerous to be handled safely.
In some cases, animals may also be euthanized using other methods, such as cervical dislocation or electrocution. However, these methods are less common and are generally only used in emergency situations.
It is important to note that kill shelters take great care to ensure that animals are euthanized in a humane and painless manner. The methods listed above are all approved by the American Veterinary Medical Association (AVMA) and are considered to be the most humane ways to euthanize animals.