I've been making these lately and I wanted to show the process.
Really the first step is to look at some real animal cookies. I got some a while back from Fresh Market. They were chocolate covered awesomeness. Also it's pretty cool that you can eat your reference material and I do whenever possible. YUM ^.^
First I start with a thin sheet of polymer clay. Then I use a pattern as a guide to cut out the shape of the animal. Those scissors are perfect for cutting small shapes.
After baking the cookie base I add the first layer of liquid clay.
Before the final layer of liquid clay I prepare the sprinkles. I use an icing tip to cut out the tiny circles. Then I cut each circle in half and roll them.
While the clay is unbaked I add the sprinkles. I place each one individually with a toothpick. I also like to let the clay sit and run off of the cookie for a few minutes before the final bake. If I don't do this the shape of the animal becomes distorted.
Here they are fresh from the oven.
The final product!