The origional way of feeding pre-kill was to take the mouse or rat by the tail and whack it on the counter trying to break its neck. The invention of the CO2 chamber has changed that. We built a CO2 chamber as a couple of our snakes take F/T and we breed our own rats. Our CO2 chamber is the home grown variety that uses baking soda and vinegar. It is two plastic tubs stacked on top of each other with the mixing chamber on the bottom and the rodent tank on top. Holes drilled in the lid and bottom of holding chamber that are glued together and presure relief hole on one side of the mixing tub. It works, but you can see everything that happens and if you watch it doesn't look very humane either. Adult rats will go crazy for about 30 seconds before finally passing out. If you mastered the old method one whack and it was done.

You did what you felt was best and no one can blame you for that. I had a snake strike a live rat pup once and the rat pup squeeled for over half an hour. The worse part is it was the first group of rat pups home grown for feeders so the wife was a little attached to them. I had to send her out of the house as she was in tears just feeding them let alone hearing this. We all deal with what we have to so we can make sure our snakes eat. No one said raising preditors like this would be easy nor is it for the faint of heart. We all do what we have to.

Now you have more info and a learning experience to grow from and hopefully you take the experience and the advice and go a different direction from now on. No one starts a hobby knowing everything. No one can blame a person for trying to make the best choice on the spot with limited information. It may have been better to come here and ask for suggestions first, but that is water under the bridge and here you are now finding out and that is probably becouse you feel something was wrong with the way you did it. Experience and sharing those experiences are what makes a hobby fun. If you never try new things you will never have any personal experience to share! Next time someone asks how to pre-kill you at least have the experience to say don't try this cause when I did the process was not pleasant!