It's good that you are looking out for your snake, but I agree with Rabernet that the method you chose was inhumane. The prey was most likely fully conscious while you strangled/squeezed it. That's a tremendous amount of pressure being put on the body, and a lot of fear and adrenaline running through the brain.

When a snake constricts a mouse, they do not strangle it at the throat. They wrap themselves around the entirety of its body, and are able to exert so much pressure on the prey that it stops blood flow. The loss of blood to the brain renders the prey unconscious while the snake finishes the kill.

That, to me, is a big difference. I hope that next time you'll choose another method of pre-killing. They say that CO2 is humane, but Carbon dioxide doesn't allow the animals to slowly drift off to sleep like Carbon Monoxide does. When using CO2, the animal is fully aware that it is suffocating. Please keep that in mind when using CO2 chambers. I completely understand the use of them, and I'm not telling anyone to NOT use one. But I do want everyone to know that it isn't an "easy, pain-and-stress-free" death like most think it is. Some people will also choose to snap the neck of the prey, thus dislocating the brain from the spinal column. But researchers have found that the brain still continues to function for a very short time once it is severed from the body. So neither decapitation nor wringing of the neck are all that humane either.

I suppose that xBrycex's method of disorienting the rat and then whacking it hard enough to render it unconscious on the first blow is the best or most humane method to pre-kill. Allowing the snake to kill the animal naturally is, in my opinion, far more desirable than pre-killing. But I do understand your situation.

The above info was just a little food for thought while we were on the subject.