Season the hens with salt, and garlic powder. Make sure to check the inner cavity to remove any bags that may contain organs. Put the hens into the Crock Pot.
HINT: You do not have to wash the Cornish hens before cooking them.
Pour the Rotel over the hens and add ½ cup of water to the slow cooker.
Cover and turn the Crock Pot on. You can cook them on low power for 6 hours, or cook them faster on high in 3 ½ hours.
Some slow cookers have the option to start on high power then automatically switch to low in a couple of hours.
Use a meat thermometer to check the internal temperature. You want the internal temperature to be 165º F.
If you can't find Rotel, you can easily use a can of diced tomatoes. Add 2 TBSP canned green chiles, and ½ cup diced onion.
You can store the leftovers in an air-tight container in your refrigerator for up to 3 days.
I do not recommend cooking frozen Cornish hens in a slow cooker. It takes a long time to cook the hens to an internal temperature of 165º F in a slow cooker and the flavor doesn't cook into the meat the same as using thawed Cornish hens.
Because most Cornish hens are sold frozen, you will want to thaw your hens before cooking them. To thaw, put the packaged hens onto a plate. Do not remove the plastic wrap they are in or they will leak all over your refrigerator as they thaw. Thaw in the refrigerator for 24-48 hours before cooking.