Yep, a gut hook works wonders for cleaning fowl. Once you've done it by hand a while, like you've done already, then you should understand the anatomy of the bird enough to be able to apply the guthook with a little thought and make a cleaner job of it. It does take a little practice, but it is effective.
As for chicken feathers, I do not consider them worth saving much. Some roosters produce dress feathers suitable enough for making flys for fishing, but I don't know what else you would want to use chicken feathers for. I've heard of them being processed for use in other livestock feed and such, but that is more an industrial application not suited to home implementation easily. I can think of much better plumage to use for decoration.
There are quite a few fowling knives on the market almost as cheap as fishing fillet knives. Check out Smoky Mountain Knife Works and you should find a good assortment to choose from. I've heard of some chicken farmers using re-fashioned wire coat hangers, but I think for the average chicken grower that is a bit too backwoodsey. As for removing feathers, I find that a bucket full of melted paraffin wax and a bucket of cold water makes the job a lot easier than the old pluck and rotate method. The wax is just hot enough to loosen up the quills without really scalding the skin, and it penetrates well, and when it sets up it is like peeling a grapefruit.
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The ultimate result of shielding men from the effects of folly is to fill the world with fools.
-- Herbert Spencer, English Philosopher (1820-1903)