I downloaded this rig from the Internet (I believe it was from Creative Crash).
The first thing I noticed from my rigging practice is how complicated the rig looks, with lots of facial controls and many for the body too in a small area.
Playing with the rig I found it is really easy to break the body. I only rotated the dog's head and this happened:
And this happened when I tried rotating the body...
I am going to look more into this tomorrow and see if there is a way around using this rig or if I should download a new one.
Here is good reference for the four legged walk cycle however, and I will use this as a guide for the leg positions for my walk.