Wrap each piece of chicken in plastic wrap (we used a high quality restaurant plastic wrap from Sam's Club but not sure if it has to be the high temp/low temp tolerant kind or not? try and see!) then layer into a gallon bag!
We butterfly and cut off the fat before doing this, but you don't have to. This process also makes portioning into 10 different bags a thing of the past! And it saves $ on gallon bags because you can throw them all into one bag and then just pop however many you need out of the bag! And sense they're individually wrapped I don't see why you couldn't reuse the gallon bag too saving even more $!
The plastic wrap also seems to keep the chicken fresher and doesn't get freezer burn as easily. Win all around!