Absolutely..... We live in Wisconsin. Today it is about 20f out. Would you go out without a jacket? Your bully has no more insulation than you do. They were bred to be muscular with very little body fat. Princess Gracie wears a fleece all the time. In her case it is also for a sense of security but she needs the warmth as well. Today she has a hot red w/ pastel polkadot fleece on.
And here is one that LariP just made for her: