Mongolian Gerbil pups
Mongolian Gerbil pups

When to breed rodents - Ethics and Care

Author: Christine, of Crittery Exotics

Breeding any animal requires a lot of thought and research, no less so with rodents. Anyone wanting to breed rodents should ideally have kept them as pets first, and so got accustomed to their care needs and enrichment before having the complications of breeding. A good knowledge of ethics, genetics and contacts with other breeders is also needed.

There are so many rodents in rescue, including pregnant or pups, that the casual 'I just want cute pups!' or 'well, it'll be fun' reasons can never be seen as anything other than a shortsighted, and selfish, view.

Please do not ever think that because you know all about one rodent, you can breed another. All rodents are different, and what works for one may kill another. Do plenty of research on your chosen rodent, make contacts, and ideally find someone who can offer advice as you start out.

Ethical breeders who improve the species in terms of health, longevity and temperament are a good alternative to pet shops; Hopefully, eventually ethical breeders will replace pet shops and so limit the amount of pets bought on an impulse, without research. Aesthetics such as coat colour or style, should always be secondary to the overall health of the animals. Any responsible breeder should both provide backup for your animal for its entire life, and also want to check in to monitor any health problems and the lifespan of their lines.

Some things to think of before considering breeding:

Parents background

You should only breed from rodents from ethical breeders, for which you know the genetic background. This means no pet shop rodents, and certainly no rescue; reputable rescues will often require you to sign an agreement that specifies you will not use for breeding purposes. This is because you have no clue what you might be breeding into your lines, genetic deformities, nasty personalities, prone to cancers, the list is endless.


If you are in rented accommodation then breeding rodents is ill-advised as you have no guarantee that your agreement will continue to support pets. Equally, if you are due to go to college, or university in a few years then you need to consider what would happen with your rodents then.

Another thing to consider is holidays or illness. Do you have someone who can step in and look after your pets in that instance? Breeders who are unable may find that they cannot have a holiday for many years.

Breeding methods

Such as the optimum breeding ratio, space required, when or if to separate dad, resting period for mum, the specialised diet and the differences between outcrossing, linebreeding and inbreeding. You will also need species specific information such as knowing that adult gerbils can only be safely introduced via the splitcage method. Remember that breeding your females may well shorten their lifespan and you must make sure that no animals has more litters than is recommended and definately no more than they personally can cope with.

Breeding ages

You don't want teenage mums or OAPs! Breeding can put a huge strain on a female rodent and you must ensure that she is in the best health and of the best age to cope with it. Breeding too young or too old can cause serious, and costly, complications.


Vet bills can be extremely costly so you must be able to pay these or you should not even attempt it. What happens if you need an emergency callout on a bank holiday because your pet is in extreme pain and needs help? Also remember you will not make a profit on selling your rodents.

When things go wrong

Are you prepared to handle dead, dying or deformed pups? Pups can be born without eyes or limbs, and sometimes the mum may kill or eat her own young. This can be also caused if you disturb the litter too soon and mum becomes stressed.

Sexing and separating pups

As well as being prolific breeders rodents can mate from a very young age so you must have the spare cages/vivariums/tanks available to separate out young before this can happen. Ideally, you should have a mentor who can show you in person how to gender your pups.

Quality of life

One thing that personally upsets me about some breeders is where they lose sight of their animals as anything other than breeding stock. Although some concessions must be made, such as a smaller, safer nursery cage for expectant mothers and their litters breeding rodents should have a similar quality of life, enrichment and space as any well-kept pet.


Although I dislike adding this term, you must be aware of how many people would like you chosen rodent as pets. Check rescues in your area to see if they have rodents of your type needing homes. See if there are other breeders near you. Many people who mention they would like a pet rodent change their minds, or may lose interest as their rodent grows older.


Never offer your rodents for free, you can always ask for people to make a donation to charity on your behalf if you don't want to take in money yourself. Rodents who are free to good homes may well end up as a meal for a reptile. Potential homes should be happy to offer photos of the habitat your rodents will be living in, and be knowledgeable or willing to research about diet and care requirements.

Any good breeder should also provide backup for their animals. This means that at any age, you should be prepared and willing to take back any animals you have bred. This is likely to be at an age when the rodents are difficult to rehome so it is likely they would then return to you for the remainder of their life. Breeders who are not prepared to do this, should not be breeding.

Choosing the next generation

As you breed, you will need to be keeping track of your animals in their new homes and with you to ensure you know of any health issues that may crop up in later life. This is one reason that culling doesn't really make sense in breeding (and that is aside from the ethical issues!) as you may well end up choosing to kill the animals that when grown would have been the best specimens. You will need to research and discuss with other breeders just how to choose which animals to be the parents for your next generation, what crossing you need to determine what your animals are carrying and what colour variations you are aiming for.

It is also important to bear in mind that a litter of say - all pink-eyed whites can be very difficult to find homes for. If a litter is likely to have little or no colour variation then you may need to time your litter in tandem with another breeder in order to mix litter colours as people will generally not be happy with a group of animals that all look the same.

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Christine runs Crittery Exotics and is an experienced animal keeper & content writer.

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