Unless you are previously experienced, it is not recommended that you start with only "virgin" 9 to 14 month female (doe) kids. Although you may know their genetic background, there can be several characteristics that are unknown. Some may be prematurely pregnant, some may have udder and teat problem, some will be late breeders or never conceive. Most will produce primarily single kids which is a less profitable situation as compared to getting more twins. When you buy more mature two-tooth (two mature incissors) yearlings or a four- or six-tooth does with a well-developed udder, at least you know they have kidded at least once. Many of those should be a regular breeders, a good milkers, and overall good mothers. The primary advantages of buying does that have not reproduced before is that they may be cheaper to purchase and they should be free of reproductive disease that may affect fertility. Most herds benefit from having does of a combination of ages which include younger ones that should be genetically superior as well as older ones that are proven producers.