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Culling Sick or Unwanted Mice Humanely Knowledge of culling is important when keeping or breeding large amounts of animals. Euthanasia by a vet is expensive and costs can rack up frighteningly when there is an outbreak of disease. For the exhibition breeder culling is necessary to keep stock numbers down. Runts must be culled, as should unwanted or useless animals, because there is simply no space to keep such animals. I began culling by using CO2 gas, but I moved on the swing method as this is an instanteous death for the mouse. CO2 is a good way for people unsure of culling with more 'hand on' methods. Both are described below. Culling by CO2 Gas Culling mice by CO2 is suitable for mice over three weeks old; any younger and they can survive for quite a long time without breathing. This is a picture of a culling chamber and CO2 bottle:
Pop the mice in the box and turn the gas on so that it's only just on and comes out very slowly. This is a picture of a regulator with the gas on, so you can see that the needle is barely off the rest point:
When the mice fall over they are unconscious, so whack the gas up full for about 30 seconds, then turn it off and leave them for at least 10 minutes just to make sure. If you can't leave them for a few minutes for some reason, take them out and break their necks by holding the head and pulling the tail. Culling by gas is a good method for those unsure of culling with a hands on method (described below). Culling by Freezing You can cull pinkies (under four days old) by putting them in an open tray and popping them in the freezer. They will lose consciousness as they get colder and will have died within a couple of minutes. They are frozen solid within five minutes. If you put them in a box with a lid it will take much longer as the air in the box will take a while to reach freezing point. Some people have said their freezers have not done the job this quickly though. If this is the case, it is better to leave them in there rather than take them out again as warming them back up from freezing will cause a lot of pain. Culling by Throwing You can cull mice of any age by throwing them, hard and fast, on to a concrete or tiled floor in such a way that the back of their neck is the point of impact. This is a good, quick method if done forcefully, particularly for kittens too old to be frozen and to young to be gassed. Culling by Swinging You can cull mice of any age by swinging them hard against or on a solid surface. Hold them by their tails and swing them in such a way that they head hits the surface first. Young kittens (under three weeks old) have particularly elastic skulls and this method can result in deforming the skull but not killing the mouse, so kittens under three weeks old are better off being thrown. Culling by Cervical Dislocation You can cull mice over three old by cervical dislocation. Place the mouse on a surface on to which it can grip and pinch the neck behind the skull firmly and sharply pull the tail. Again, young kittens have very elastic bones so throwing them is better. Confidence is Key With hands on methods such as throwing, swinging and cervical dislocation, confidence is key. These methods WILL work first time and result in an instant death for the mouse - but only if they are done quickly and forcefully without hesitation. Swinging and throwing must be done on/against a surface that has no 'give' in it whatsoever to ensure maximum force in the impact. Culling Mice to Feed to Carnivorous Pets All of the methods described above are fine for culling mice to feed to carnivores, although don't ever feed a carnivore with a mouse you have culled due to sickness. |
