Feeder FAQs -- Breeding Q's

[JLC]

11. What kinds of enclosures are good for rat colonies?

Heavy plastic tubs work well in a rack system. They need to be smooth so the rats won't chew on them and heavy enough to resist some natural chewing (offer your rats other things to chew like bones, etc. to avoid some of this behavior). You can find many online directions for building your own rat racks or purchase them ready made. If you are only breeding a few rats and don't need a rack, you can just add wire to the tub lids to increase ventilation. You can also choose to use commercial rat caging. Whatever option you choose, it is important to offer your rats an enclosure big enough to move around comfortably and not be overcrowded. You can use glass tanks but they often don't have enough ventilation and tend to build up ammonia smells very quickly. They are also heavy to lift and clean properly.

12. What are some common illnesses or genetic problems that I should beware of?

Rats are generally very hardy creatures but tend to be inbred excessively. Because of this you do see some sudden deaths due to genetic faults. Raising and maintaining your own breeding colony with an eye to out-crossing will avoid these problems. Rats are more prone to cancerous tumors than any other rodent. It's best to put them down quickly and humanely in that case. Poor mothering/maternal cannibalism may have a genetic factor so if you see a consistent pattern, feed off that female or find her a home as a pet. Alternatively good litters/good mothering can mean you want to keep some of this female's daughters for your next generation breeders.

13. When (if at all) should I pull the male out of a breeding tank?

Some breeders remove the male as soon as the females show signs of pregnancy, some do not. Rodents can re-breed within days of producing a litter though some female rodents will not allow the male near them while they are nursing. It is up to the breeder to decide which way to go.
14. Is it really cheaper to breed my own feeders?

That depends on your costs for housing, bedding, feed mix ingredients, etc. as well as your own time investment versus what it would cost to either buy live locally or order frozen/thawed in the quantity and sizes you require for your collection. Sometimes it's not about cost as much as convenience of having the right size at hand at all times as well as the satisfaction of raising your snake's high quality food yourself.

15. What ages are the best for rats to begin their breeding careers? When should they retire?

Female rats should not be bred before 4 to 5 months of age but no later than 9 months for their first breeding. They can breed past 1 year of age but as they get to 1.5 years of age their litter productivity will drop significantly. Males can breed from sexual maturity up until they die. Their productivity as a stud rat will drop however as they age, though not as significantly as the females.

16. What ages are the best for mice to begin their breeding careers? When should they retire?

As with rats, mice need to be separated according to sex by 4 to 5 weeks of age to avoid premature breeding. Female mice have a pretty short reproductive life. They shouldn't be bred until they are about 12 weeks old and not after 8 or 9 months of age when their fertility will start to drop sharply. Male mice, like their ratty counterparts, are generally fertile well into their last months of life.

17. How long is gestation for rats? For mice?

Rats - 21-23 days generally

Mice - 19 - 21 days generally

18. Is it messy when they give birth?

A healthy female rat or mouse will clean up all signs of birth including eating all afterbirth. This means a very clean birthing process with little mess or blood involved. This provides the female with needed nutrients to produce milk for the first day or so without having to leave her nest to seek food and water (though of course lots of food and fresh water should always be present for all rodents, especially nursing females).

19. How often can a female rat have new litters? A mouse?

Females can breed back to back litters so can produce a new litter as they are weaning their current litter. Just because they can doesn't always mean they should however. It is up to the rodent breeder to decide how to control the colony's reproduction in order to produce needed feeders, be cost effective but also not burn out good breeding females or produce less than healthy young because the female is worn down.

20. If I take away all a rat’s newborn babies, can she get pregnant again right away?

She can get pregnant whether or not she has young with her. If a male rodent is present and she is in estrus (heat cycle) she will breed whether young are nursing or not. Some female rodents will reject the male's advances while nursing, however, this is not a reliable way to ensure colony reproduction rates.

21. Is it OK to keep multiple rat/mice moms together?

Some rodent breeders set up females alone, some keep reproducing females together. If you choose to keep them together watch for the females dragging the young around excessively from nest to nest or one female doing the majority of the nursing. Some females will assist each other, some will not. If you find you are losing pinks to damage from the females, then separate the females into tanks alone with their own litters.

22. What is "myco?" What are its symptoms and triggers?

Myco (Mycoplasma pulmonis) is an organism found in almost all rats coming out of the pet trade. It is carried but not always expressed as an active infection unless the rat is overly stressed or otherwise ill and its immune system compromised. It's usually seen as a respiratory or genital infection. It's passed from rat to rat by direct contact, through sexual contact or from female rats to their offspring during birth. It can also be airborne for short distances. Symptoms are sneezing and sniffling, their coats look very rough, head tilting or shaking if their ears are sore, squinting in bright light and porphyrin staining around the eyes and nose. They may hunch over and be very quiet, not scurrying around like a healthy rat does. The genital form will cause loss of litters or very small litters as well as infertility. If the rat cannot shake it off or get vet care it can get worse and lead to death which can take weeks or months.

23. What is "megacolon?"

Megacolon is a disorder of the nerves of the colon occurring during fetal development of the rat and thought to be genetically related to certain coat colors. You see it more with BEW (black-eyed white), husky, blazed, split-capped or other high-white lines of rats (excluding albino's generally). The rat will appear normal at birth but when it is old enough to eat solids it will not thrive as it cannot absorb nutrients properly nor defecate normally. Sometimes it is late onset, 2 to 5 months instead of 3 or 4 weeks of age. It is suffering so please put it down promptly and humanely. If you are getting any megacolon in your litters do not re-breed the adults that produced these offspring.

24. What is "porphyrin?"

Often called "red tears" and mistaken for blood, porphyrin is seen around the eyes and nostrils of rats. Porphyrin comes from the Harderian Glands that are located behind their eyes. Seeing a bit of porphyrin here or there is no problem, a lot of it coming from just one eye can mean a blocked tear duct or a fleck of bedding stuck in the rat's eye so just flush that gently with a bit of clear, warm water. Excessive porphyrin staining from the eyes or nose is a sign of stress or illness. Check the rat for general health, make sure the bedding is fresh and not too dusty, check for proper ventilation, make sure the rat has sufficient food and water available and make sure you are not overcrowding your colony. Porphyrin, in and of itself, is not a problem. It's often more of a symptom of a problem. Healthy, happy, productive colonies should not show a lot of red tears.