Psyllium husk as a fibre source in a raw food diet?

Not necessary. At all. Fiber doesn't replace fur, and fur really isn't needed anyway...it's a cutesy idea that dogs need to eat fur to digest well...but it hasn't played out in reality. The theory was a good one, but it's a failed one. Dogs do fine on a raw diet with no fur/extra fiber. Also "raw food" diet sounds like you're feeding veggies...feeding veggies = Waste of time....they're only digestable if finely pureed (which damages the cell wall) or cooked (which also damages the cell wall). And even if you puree or cook? The nutrients in the plant matter aren't necessary if you feed a well balanced raw diet soley containing animal protein sources including organs.