In an effort to get my O's to eat a well balanced diet I make my own food. It's quite easy to and inexpensive as well.
To freeze the food you can just place it in a zip lock bag and place flat on a cookie sheet. To create my own cubes I use a piece of plastic egg crate the kind used for lighting. I place a piece of saran wrap on a cookie sheet then place the egg crate on that then fill with food and freeze. Once frozen the cubes can be popped out and stored in a zip lock for future feeding.