The original drawing was monumental. It required two pieces of paper and four scans to create the composite. The final composite is 24 x 16 inches at 350 dpi.
At this point I found textures, from my favorite texture website, such as close-ups of lichen (skin), leaf veins (wings), stippled metal (plates), and ceramic glaze (horns). I used a rubber-stamp tool in PhotoShop to paint in areas with the texture I found. Once the textures were in place I adjusted the colors to fit the palette. Then, I added low-lights (shading) using a multiply layer, in PhotoShop, and high-lights using a overlay layer. Finally, I painted in some details that did not have any texture (tongue, beak, eyes).
Here is a detail of the final picture.
Click on each picture to see a bigger image.
Click on each picture to see a bigger image.