I used those bags last spring with great success. am using them again this weekend on 35 CXers.The few meat birds I've done I have vacuum packed. I don't like doing it. They're way too wet to make it easy. And they're too big to fit into a normal bag.
There are bags available that seal when filled with the chicken and then dropped into hot water. They're what I plan to use this time.
I live in Amish country, and was advised to use wax butcher paper, then place inside plastic storage bags. Not the zip ones, the ones you use with a twisti tie . Been doing this for awhile and, contrarialy, have never experienced 'freezer frost'. And the birds fit just fine.