To use shrink bags do the following:

Drain birds from chill tank. Make a drain rack (see below) out of PVC pipe that will hold 8-10 birds.

With the birds sitting on the rack with their “head” up, slide a bag down over the chicken. Take one bird off the rack, turn it upside down and push it all the way in to the bag. Squeeze the legs together and gather the bag tightly around the legs. Then spin it to form a “pigtail” out of the excess bag material. Staple the bag. The stapler should go AROUND the pigtail  and not through it. Then pierce the bag at the breast area twice to let the air out.

An alternative to putting a hole in the bag is to evacuate the air from the bag with a small piece of tubing mounted on the end of a vacuum cleaner. Then twist the bag while the tube is still in the bag and pull the bag off the tubing continuing to twist and seal the bag.

Dip the bird into 180-200° F hot water and swirl it around for 2-3 seconds holding onto the excess "tail". You may also want to use a pair of tongs to hold the bird down (it will want to float), PUSH the bird  into the hot water. There should be a rush of  air and lots of bubbles so be careful not to get burned. The shrinking is done in an instant, pull the bird out, remove the bird and place it in an iced cooler until all are done. When all done  weigh the bird and put a sticky label (available below) right over where the bag was pierced at the breast.