Silkies are a breed of Bantam, but are so distinct from other types of chicken that they deserve their own spotlight.
The most striking element is their permanent down - the feathers of adults are not substantially different from that of chicks. It will keep them warmer, but they stay fluffy and soft throughout their lifespans. They also have five toes (one more than usual) and black skin that makes it easy to spot molting. Some are "muffed," meaning they have extra fluff around their earlobes and under the chin.
The upside of silkies as pets is that they are very docile, they will not be spooked by being handled, the noises of other pets, or children. However, this translates to intense broodiness, as they will often sit on eggs all day and have to be moved daily to retrieve from the nesting box.