How should raw, unfrozen chicken be wrapped for freezing?

Pre-packaged, raw, unfrozen chicken sold in supermarkets is generally wrapped using a process called modified atmosphere packaging (MAP). The air in the package is replaced with gases that don’t interact, like oxygen does, with food components. Products wrapped this way may be puffed up on top. Products should not be frozen in this type of packaging because water can migrate from the food to  the head space (the bubble)  created by the gases; the result will be dehydration and freezer burn. Also,  the plastic wrap over the head space can tear if something heavy is placed on it. Then the product will dry out and develop freezer burn. 
 
Source(s):
Susan Brewer, Ph.D., University of Illinois, Department of Food Science and Human Nutrition