Did you know that you can needle felt muslin doll or animal bodies too? You can, it's actually a time saver. The following link goes to one of my site pages... "Ms. Siamese" is felted over a muslin wire armatured doll body.
I've added a picture ... If this picture comes up you can see that I'm in the progress of felting over a muslin rabbit, I cut off his ears, eyes, tail and wiskers. For the ears now attached I have needle felted over a sheet of felt. I cut out from the felt sheet my ears and then using my foam work base needle felted the wool onto both sides. I have extended the face and legs, he's not finished yet but will be soon.
Manufactured bears that are string jointed also work as a base, pull them apart and felt the body, arms, legs and head into anything you want. The manufactured critter is just your core. You can find these critters at Jo Ann Fabrics, Michaels or other craft stores. Most are between $1 and $5.
All these wonderful ideas and never enough time in the day to try them all. I have done some needle felting and loved it but am trying to stat focused for awhile on my Koalas and the "Kookaburra" which is still at the scetch stage. Maybe I should needle felt part of him.
Can I get a fur effect for the chest? And how do you add mohair to the wool? Do you buy it as you do the wool?
"Furry" effect ... Judi's idea is worth a try and should make an interesting effect. Another idea might be to needle felt the dog completely shaving off the hair. If you felt your dog and then take a tooth brush... a clean one and lightly brush the felted area it will become "fuzzier"
Or just lightly felt in the chest, as I did the rabbits tail in my first post on this subject (you can't see it very well) or go to my site - the Virtual Catalog and check out my poodles ears. I actually felted the ears as one piece on my foam work base leaving the ends unfelted and then just lightly needled the ends to shape them. I then attached the ears to the head of the poodle. Hope this helps.