How to store parts of whole chicken for long time?
When you want to freeze things so that they don't stick together, you need to freeze them separately and then combine later. So, for example, if you're freezing blueberries, you can freeze them on a cookie sheet and then combine them in one bag or container. 

For chicken, I wouldn't advise freezing the pieces uncovered (as you do for blueberries). Instead, I would package the pieces in containers that only hold one meal's worth. You can always defrost more than one package if necessary. 

This could be a plastic container or wrapped individually in plastic wrap or aluminum foil, or even a zippered plastic bag. Any of these would allow you to unwrap individually and defrost.