Time from start to completion: about 1 hour, that includes drying time (and cleaning faces and getting snacks and laying babies down for a nap)
First, you will need: Freezer paper that is located by the foil in most grocery stores, paint I'm using acrylic paint because I haven't been to the store to get fabric paint, iron, ironing board, x-acto knife, paint brush, the image to stencil and something to stencil on, I'm using a onesie.
Trace the image onto the freezer paper. Freezer paper has two sides, one shiny, one not. The shiny side is what fuses to the fabric, so trace your image with the shiny side down, matte side up.
Cut the image out to create the stencil. I'm using three colors for this image, but I only needed two different stencils. 
One for the body and the letters. The body will be yellow and the letters black, you just have to be careful. Another stencil for the legs and beak which will both be orange. For the letter P's, I cut out a tiny square of paper that will fit in the circle of the P so it won't be painted on and it will look like a letter p, not a stick figure with a big nose.
Next, turn your shirt inside out and iron a piece of freezer paper on that is big enough to easily cover the part of the shirt you will be painting on from the front. This prevents any bleeding through the front onto the back.
Turn the shirt back to the right side and iron on the first image. I am doing the body and letters first.
Immediately call your five year old in to do the painting. Paint the body yellow
and the letters black. Just be careful not to get black on the yellow.
Let dry. While waiting read and marvel at The Invention of Hugo Cabret.
Peel the stencil off and yipee, it's starting to look like a chick.
Iron on the second stencil. I traced the body of the chick so that I could line it up with what is painted underneath.
Paint orange.
Let dry and peel off.
Almost done, it's not perfect, but I like it that way.
I used the head of a pin to paint an eye.
Now the chick can see properly. Peel off the paper from the inside (I save this paper to iron on the inside of another shirt.)
All finished and waiting for a new baby!
Have fun and beware, once you start it's very difficult to not imagine things to stencil! Here are the directions again for easier printing.
You will need: Freezer paper that is located by the foil in most grocery stores, paint, iron, ironing board, x-acto knife, paint brush, the image to stencil and something to stencil on.
Trace the image onto the freezer paper. Freezer paper has two sides, one shiny, one not. The shiny side is what fuses to the fabric, so trace your image with the shiny side down, matte side up.
Cut the image out to create the stencil.
Next, turn your shirt inside out and iron a piece of freezer paper on that is big enough to easily cover the part of the shirt you will be painting on from the front.
Turn the shirt back to the right side and iron on the first image.
Immediately call your five year old in to do the painting.
Let dry. Peel the freezer paper off and throw away.
Iron on the second stencil.
Let dry and peel off.
Peel off the paper from the inside of the shirt. Set the paint with an iron or by putting in the dryer.
