Most of the time, when a dog eats fur, it's her own. A dog may chew on herself or eat her own fur because of illness or boredom, but if she's eating another dog's fur, it's likely a simple compulsion. It doesn't accomplish anything, but rather is simply pleasurable for her. Eating fur isn't healthy, though, and stopping her from doing it while she's still a puppy will prevent the behavior from becoming a pattern throughout her adult life.
Sweep your home regularly to keep bits of tempting fur off the ground and out of the carpet.
Brush your dogs regularly, especially if they are prone to shedding. Do so when they are separated, and do it in a controlled environment such as a closed-off room or even the yard. This prevents dead hair from falling out throughout your home. How often your furry friends need to be brushed depends entirely on their breeds.
Give your puppy soft toys in addition to hard ones. While hard toys help her teethe and keep her teeth clean, if she demonstrates a preference for chewing on softer things like fur, go ahead and give her something like a plush toy.
Scold her verbally when you catch her in the act and take away the fur. Immediately after, give her a soft toy that she doesn't typically have access to, and praise her when she plays with it. This teaches her that chewing on fur is bad, but chewing on toys is good.
Play with your puppy. Inappropriate chewing of any kind is a reliable indicator of boredom, especially in puppies -- they have plenty of energy to burn. Make sure that she gets plenty of exercise and playtime every day so she isn't looking for ways to get her kicks elsewhere.