A rat's food must be provided in a clean, durable food dish or hopper. Food dishes should be made of ceramic or very hard plastic to resist damage from chewing and should be kept on the lowest level of the cage, unless securely fashioned so it doesn't get knocked over. Food hoppers come in metal or plastic and often hang on the outside of the cage, with the dispenser portion sticking through the bars. These hoppers are probably the best free-feeding option, as they are higher up and keep the food away from soiled bedding.
Even if your rats take their food out of their food dish immediately and stash it somewhere, a food dish is still good to have. Because of the urine and feces in a cage, you should never put their food on their bedding. Having a food dish also lets the rats know where they can expect their food. If your rats keep storing their food in a different place, try moving the food dish closer to that location, or perhaps even block that location if it is the same place they are urinating.
All food dishes should be cleaned at least every time you clean the cage and immediately if they show signs of urine, feces, or molding. Food dishes can be washed just like human dishes.
Water Bottles
Water bottles are much safer and more hygienic to use than water dishes, which can easily become spilled, soiled, and contaminated. Most water bottles are similar, with a plastic or glass reservoir that screws on to a plastic base which holds a metal sipper tube with one or two metal balls inside the tube. When the rat licks at the tube, the ball moves back, releasing a bit of water. Some water bottles are made of a glass bottle with a rubber stopper and another small glass tube from which the rat drinks. Though these do work, they are not as effective as the metal ball type water bottles and tend to drip more often. Yet another kind of water bottle does not have a ball, and instead has a thin metal bar that, when manipulated, releases water. These water bottles often don't rely on the vaccuum effect and can be filled via a lid on the top of the reservoir. Though this can make it easier for you to fill, some rats will not instinctively know how to use them and you may have to show them.
Water bottles must be cleaned at least every time you clean the cage, and can be done so with a bottle brush. Cleaning inside the metal tube is necessary as well, which can also be done with a small bottle brush.
Free Feeding
If you are feeding a commercial diet, it is best to free feed. Rats will not over-eat and therefore can be given plenty of food without worry of them eating too much. A nice sized food dish or hopper should be filled at all times, allowing the rats to choose when they would like to eat. Fresh vegetables and fruits should still be supplemented, but should not be allowed to sit in the cage for too long, as they can spoil. Home made diets containing fresh foods should also not be allowed to sit in the cage for too long. With home made diets it is almost always better to have a feeding time instead of free feeding.
Free feeding is good for people who do not have the time to personally feed their rats every day, or have varied schedules that would make a static feeding time impossible. It is also good for the rats, as they have very high metabolisms and must eat lots of small meals throughout the day.
Feeding Time
Having a set feeding time, where you feed each rat cage a set amount, can be very beneficial to the rats, if you can find the time to do it. If you do it at the same time every day, your rats will come to expect it and will love getting the attention from you as you feed them. It will help them to be more sociable, as they will associate you with bringing the food, not just a food dish. It also gives you the opportunity to socialize with your rats daily, and you can asses their conditions and see any signs of illness or injury that may have occurred in the last 24 hours.
Feeding time is recommended for home made diets and fresh foods, which will spoil if left in a dish for too long, but it can be done with any diet as long as you make sure your rats are getting enough. To find out how much your rats eat, overestimate at first. By feeding time the next day, see what is left over, discard it, clean out the food dish, and feed that much less next time. It may take some experiments to see how much your rats will eat. If they eat every bite and still seem hungry, go ahead and give them some more.
Though it is not necessary to feed each rat individually, do make sure that each rat is eating enough. Some bossy rats will steal food from the more submissive ones, which can result in the rat not getting enough nutrition. If one or more of your rats are losing weight, you may want to watch them carefully to see if this is the cause, or you may want to provide some lab blocks as free feed between feeding times so they have at least a little something to eat.
