There are three primary types of breeders: Responsible Breeders, Casual/Hobbyist Breeders and Profit Breeders. Before deciding to breed your pets, you should determine what category you will fall into.
Responsible Breeders are careful to obtain their breeding animals from good sources (such as other establish breeding lines). They will carefully monitor the blood lines of the animals they breed to ensure that they are as free as possible from common genetic defects. They will breed not only for color and markings, but for a healthy, intelligent and even tempered animal. They will only breed as many animals as they can keep themselves or find wonderful homes for.
A Responsible Breeder often does not make much, if any profit from breeding their animals. They will also take back any animal that they have bred that needs to be returned by it's new owner for any reason. They will also adopt out pets that are not of breeding quality with a contract that says they will not be bred by their new owners, to prevent the spread of unfavorable genetics.
The Casual or Hobbyist Breeder will often breed animals out of interest or novelty. They are often not selective of genetics, or where their animals are placed once they have reached weaning age. Many Casual Breeders will end up sending a surplus of animals to the shelter when the care of multiple animals becomes too heavy, or send them to a pet store believing that they will all find "good homes" because they are "cute and friendly".
Many people will casually breed their animals for a variety of reasons, although there are many more reasons not to participate in casual breeding.
The Reason: "I want my children to experience the miracle of birth"
The Reality: Breeding your pets is not a good way to show your children the miracle of birth. If you breed a small animal around children, you should be prepared to explain to your children if the mother cannibalizes her babies, turns and kills the male (or the male kills the female) during breeding. Often, an excited child will not be able to wait to hold the babies of their new hamster, and this can result in a traumatic experience when an upset mother begins killing her litter. There is also the possibility that the mother will die during birth, and can be the source of a traumatic experience for a child who takes part in raising babies and then is forced to get rid of them.
The Reason: "Baby ______'s are so cute!
The Reality: Yes, baby animals are very cute. However, they also need LOTS of handling time while they are growing up to become mellow, gentle animals who can happily interact with humans. Baby animals will also bite, jump, scratch and be wild little things as you teach them how to be friendly members of the family. You will also need special housing with special bar spacing to keep the babies safe, as well as special foods for them to start on, and extra cages to gender separate in when they reach sexual maturity.
The Reason: "My friends all love my _____ and want one of their own"
The Reality: Recommend that your friends go to a shelter or rescue organization where they can save a life instead of adding another pet. Remember, if your friends really adored the animal/species that much, they probably would have already gotten one of their own. It's not uncommon to find that all of your friends who adore your pet hamster and say how they wish they had one of their own, don't actually want one if they have to take care of and play with them every day.
The Reason: "_______s are worth money, I could sell them!"
The Reality: That would be assuming there is even any market for the animal you are breeding to begin with. Unless you are running a very good breeding program (see: Responsible Breeder) there is no incentive for new owners to purchase your animals for any more then they might purchase a feeder at the pet store. You will also have to spend money for habitats, food, bedding and medical care, besides the cost of your time to raise and socialize each baby a day.
Keep in mind that the reason why rescues exist is that there is already a surplus of pets that do not have homes. There will not necessarily be a market for your pets if you breed them at home. Leaving your small animal at a shelter means you are leaving them at a high risk for being put to sleep.
The Reason: "I love my ____ so much that I want one just like them."
The Reality: Animals are as much individuals as people, and will no more be a copy of their parents then you are a copy of yours. There may be similarities in disposition, but you are not guaranteed to have a baby just like your current pet, and will be risking their health and welfare to breed them. You will also be giving up time you have to spend with them in socializing their offspring.
The Reason: "There's only going to be a few babies, we can keep them."
The Reality: The idea that there will be 'only a few' can get you into a lot of trouble very quickly. To use mice as an example, a female mouse can conceive at four weeks of age. Gestation takes between 19-21 days. The average litter is between 5-8 pups who will not be weaned until 3 weeks of age. A large litter can be around 14 pups. This means you will have a one week window in between when your mice will be weaned and when they can start breeding with each other.
This means if you have one pregnant mouse, in one month it's eight offspring can potentially have 80 mice, in two months it's offspring can have 400 mice. Next month those mice can have 2000 more pups. Are you prepared to give a home or find the proper homes for all of them?
Gender separation is very important and it can be very hard to do on youngsters before it is too late.
The Reason: "We can always find a home somehow for them"
The Reality: Pets that are given away for free or at a low cost to people without talking about them about the real care needs and responsibility of pet care are at a high risk to be neglected, abused or abandoned. Many people who tire of a pet will "let them free" out into the wild, which often means the pet that you breed will suffer starvation or dehydration before dying if they are not killed by a predator first. Small animals abandoned at shelters are at a high risk for euthanasia as many people do not even think to go to a shelter to adopt a small animal.
Breeding for Profit
Breeding for Profit seldom works unless it is at the expense of the animals. If you are not breeding Show Quality animals and competing in species specific shows, and building a reputation as having exceptional stock, your average small animal will not net you much profit at all.
Here we have outlined the basic cost for breeding, assuming that you are purchasing rats for breeding from a common pet store (and not more expensive rats that are good breeding stock), second hand habitats and supplies, are not purchasing any toys, and do not need to spend any money for medical care:
Purchase 1 Pair of Breeding Rats - $20
2 Cages, 1 Suitable for Breeding and 1 to house the Male Rat - $60
Enough Rat Food to last breeding pair and resulting litter from the First Mating to Weaning of Babies - $30
Enough Aspen Shavings to last Breeding Pair and Litter from First Mating to Weaning of Babies - $20
Water Bottles & Food Bowls - $20
Your Initial Investment: $150
On a base level, we will also assume that you are spending one hour a day socializing all of the animals, two hours a week feeding and changing water bottles, and two hours a week cleaning all of their cages and supplies. This totals to 11 hours a week of your time invested.
Now, assuming that your female rat has ten babies that you sell for $10 each, and socialize for one hour a day until they are weaned (weaned at four weeks and kept until five weeks to ensure they are healthy and thriving past weaning) and ready to go to new homes. You will have lost $50 and have invested 35 hours in socializing the babies without making any profit.
Assuming that you breed and sell enough litters to pay for your initial investment of supplies, you will be making $5.50 an hour for your time. With this money, you will also need to purchase food and bedding for your animals. You will also need to provide medical care for any rats that become ill during this time, or purchase extra cages if a group of rats starts fighting and needs to be split up.
Does it still seem so profitable?