Feeder Mice 101

Breeding your own feeder mice is a great way to save money, always have food on hand, and oh – did I mention save money? Before you get started with elaborate racks for breeding, and expensive cages please consider the costs, and time you will need for this. Caring mice requires the same time and effort as having other pets and should not be overlooked.

Is breeding mice for everyone? No, but its always nice to have the option. Here we cover the basics:

To get started you will need the following:

  • 10 gallon tank aquarium
  • Mesh cover for aquarium
  • Heavy food dish
  • Food (consider seed mix or feeder blocks)
  • Water Bottle
  • Pine shred (or your choice)
  • Hide (milk carton, egg carton…)
  • Mice (1 male and 4-5 females)

Why pine? We’ve found pine to be relatively inexpensive and cover odor better than most cheap shreds. Its easy to clean, and helps provide warmth for your colony.

Why the odd ratio of male to females? Females go into heat every 3 days, so its best to have the odd ratio for the male. Having anything less than this would be inefficient for fast growth, but depending on your needs you can always consider less. Adding another male to the harem will cause aggressive behavior. Often males will fight to the death. Adding new females to an established harem can cause these same issues.

Breeding mice is considerably easier than breeding snakes! Having them harem dwell together eliminates the need for introductions. Allowing the mice to copulate, you will notice the female is pregnant by a sac-like protrusion from her belly. Its noticeable, so don’t worry! Gestation lasts 18-21 days. Once she is pregnant, I’d recommend removing her from the harem to her own breeding cage about day 12 so she can become familiar with her new surroundings. If you don’t there is chance of the others killing the young, so just eliminate the problem instead. Make sure the breeding cage is sterilized, and roomy enough. If it is too small, she may kill her offspring because of feeling cramped. Do not disturb the mother during the week of anticipated delivery. Some mice may feel watched, and not appreciate this sense and cannibalize their own offspring. Disturb only for feedings, and fresh water.

Nursing: should last about 3-4 weeks and then the female may return to her harem.

Maturing and Breeding Age: It takes about 6 weeks for your mice to mature. While you can breed at this age, we’d recommend waiting until at least 8 weeks before getting started.

Litter Size: Litters range from 5-20 pinkies, on average 12-15.

Temperature: While snakes are more demanding, success has been seen with sex of offspring based on temps. The cooler, the more females. The warmer, the more males. Having a steady temperature of 70 F should yield a healthy mix.

Breeding again: It is said you can actually breed again 24 hours after delivery. If you have a healthy harem of 4-5 females, I’d wait a bit longer. Remember heat is every 3 days so you’ll have another chance in no time.

Hopefully this gives you an overview of breeding feeders. These same methods can be applied to rats. Feel free to contact us if you think some info should be added or changed!