Glad to hear they're doing well.

Everyone else has thoroughly covered diet, I want to commend you on tub feeding them!!! It is DEFINITELY my preferred method, allowing me to know who eats what, since most of my garters are cohabbed. In addition, I find that feeding time is a wonderful time to clean the tanks. The inhabitants are already out and happily eating. Lastly, there is little chance you will ever have a snake with complications from ingested substrate.

Good job, and keep up the good work.