I've switched to using freezer bags. Those containers were taking up way to much room in the freezer. Now when I have an excess of meat for Prancer that needs to be frozen I chunk it up, lay it on a wax paper lined cookie sheet, freeze it and then transfer to a freezer bag. Takes up alot less room and I can pick and choice / mix and match what meats I'm going to give her on any given day. I also have freezer bags with individually frozen chicken hearts, beef heart slices, turkey meatballs, and chicken gizzards (I call the gizzards 'doggie chewing gum' - my vet recommended them to keep teeth clean - seems to be working, they're certainly not worse).
My next batch of veggie mush will get bagged instead of containered also - I'm going to start freezing it in ice cube trays and transferring it to bags.
I don't know why I didn't think of going totally bagged sooner - its alot easier to fit them in since they can conform to whatever weird shaped spot I have available in the freezer. Only took me 2 years to figure it out LOL