I have two pet rats and since rats are omnivores, they like to eat insects. There aren't too many big insects in downtown Milwaukee that can satisfy the hunger of a gluttonous rodent, therefore I decided to breed some insects myself. Since most pet stores carry crickets, I decided to go with that species.
I found a nice plastic critter keeper at a local pet store and decided that it would be best for the job. Some people use open plastic tubs, but I don't want to have any jailbreaks since crickets are noisy and eat linens. The keeper I bought is solidly built and has a tight lid to minimize chances of escapes.
I filled the container with a layer of potting soil for the crickets to lay eggs in and dig into. I also added an empty toilet paper tube for them to hide in from the light. For moisture, I added a crumpled up paper towel soaked with water, which I soak every day. The crickets use this to drink water, otherwise they would dehydrate and die. I also feed the crickets oatmeal, which they seem to enjoy, as well as lettuce.
After putting all of this stuff in the container, I put in 15 crickets. I should have gotten all full size crickets, but I ended up with a bunch of young ones that won't be able to reproduce for quite some time. They seemed to like the environment and started grabbing oatmeal flakes to drag off and munch on.
They also seemed to be drinking from the paper towel, but after 3 deaths I am beginning to wonder if they need something better. I have read that using fresh slices of orange may work better since they can eat it, as opposed to inedible paper towels, so I will try that. I am hoping that I won't have too many deaths, or I will have to buy more crickets to seed the colony.
So far, I have fed the rats the three crickets that died, and they were so excited that Orpheus nipped my finger when he grabbed the cricket from me. I am hoping to set up a hunt where there are a number of crickets running loose and the rats will have to chase them down like they would in the wild. That will make things more interesting than simply handing them the crickets.