Rats need time outside their cage every day to explore and play. If you are too busy to supervise your rats closely, it is a good idea to create a play area rather than letting them just run loose. Rats have a tendency to chew things, including cables, books and anything plastic. If you aren't watching your pets carefully, you might discover various items shredded up later. You can create a play area in a pen or assemble various items to set up in a small, secure room such as a bathroom.
Collect old cardboard boxes of various sizes and cut rat-size holes in the sides of the larger ones.
Put a few healthy treats into the smallest boxes and close but don't cut any holes. Your pets can discover how to get the treats out, usually by chewing.
Connect some of the holes with large cardboard tubes big enough for a rat to climb through. If you don't have any such tubes, make your own by rolling up pieces of stiff cardboard and securing with tape.
Create a tower by securing gradually smaller boxes one on top of another with tape. Rats enjoy climbing.
Place all your cardboard items in the pen or small room with the tower in the middle.
Put your rats in the play area and leave them there for as long as possible. If you are using a pen, keep an eye on them just in case one finds a way out. This is more likely with female rats.
Throw away any cardboard boxes or tubes that become soiled and replace with new ones next time.
Anything that rats can climb over, through or up can be added to the play area, provided it is made from nontoxic materials. Old clothes, wooden pallets and plastic children's toys are all suitable. Wash or replace as required. Training your rats to come when called helps if they escape during playtime. Whistle or call before you feed them each day and they will quickly learn to run over.