Sable ferrets are the most common.
I have purchased a few ferrets and they've all been from petco. Most places will sell ferrets between 90$ and 150$. I do not know if there are specific "breeds" that can cost more or less.
Ferrets are susceptible to a lot of various diseases. The most common is canine distemper. Ferrets are susceptible to feline distemper as well. Ferrets rarely get rabies but precautions should still be taken. There are many other common diseases that ferrets are susceptible to also. Fleas, mites, and physical injuries are not diseases but are quite common.
There are no 'breeds' of chinchilla, but the most common colour is a standard grey
Angus cattle are the most common of the beef breeds and Holstein cattle are the most common of the diary breeds.
Small terriers
Yes according to the AVMA they are the third most common domestic pets.
no
Artificial selection.
They are not as common as brown. Also, Ferrets with a whit head may be blind.
You can get Marshall bred ferrets from most Petco stores. You can identify a Marshall ferret by the two dots in the ear. This is a tattoo that identifies the ferret as fixed and descented. Marshall farms also breeds ferrets for lab research but Path Valley Farms does not. I would not recommend buying a Triple F ferret, they are being investigated for cruelty to animals.
There are numerous dangers to ferrets, You have to ferret proof their environment, ferrets need to be handle by a responsible person (no small kids), ferrets need a special diet, they are carnivores (meat eaters) and cannot digest fruits or vegetables. Ferrets can be prone to illness and disease if not taken care of properly. They could be perceived as prey by some dog breeds.
The most common hamster is a Syrian hamster, but there are other less popular breeds such as Russian dwarfs and Chinese