Chicken fat is currently abou $0.50/lb for the higher quality (< 4% FFA) referenced above. High compared to the target selling price (current price of diesel), but nowhere near the $/gallon quoted in the comment.
It took a while before I even remembered this thread. As I recall, aside from my comment being mostly just a snide joke, I relied on retail food grade pricing for my calculations. The article didn't cite a price and I didn't have the inclination to contact commercial chicken farms to inquire about what they would charge for bulk quantities. I further reasoned that should the practice of fat -> fuel conversion went mainstream it would skyrocket the price to rival retail levels.
For the record here's the source of my price estimate:
http://lowesfoods.grocerydirect.com/pd/Empire_Kosher/Rendered_Chicken_Fat/7_oz/00071627008090?clksrc=gproduct
Priced at $3.79 per 7 oz. package it works out to about $8.60/lb, a little less than what I came up with oh those many years ago.
Cheers!