You can feed your rats a piece of dry dog food every now and again just as a treat, but don’t make it a regular part of their diet- it contains too much protein and can cause kidney problems.
Carefresh is a great bedding- very soft on the feet. If you have any wire flooring in the cage, you can cut some rubber no-slip bath mats and use them as flooring. (This is what I do for the second and third levels of my rats’ cages.) They usually won’t chew on this because rubber tastes pretty horrible to them. It’s also very easy to clean.
Rats, unlike most hamsters, are terrified of those plastic balls to roll around in. I’d suggest not getting one. But plenty of exercise is a great idea- rats love to come out and run around, usually on beds. Some rats will leave little drops of urine behind them as they run around. It’s a very small amount, not enough to stain or smell. Just put an old towel or blanket down before you let them out.
Respiratory problems are common in rats; a few sneezes now and again are nothing to worry about, but constant sneezing and wheezing is a problem and you need to see your vet. (Wheezing becomes noticeabe when the rat is running around- hold him/her up to your ear and listen. A soft hooting sound means trouble.) Aquariums allow ammonia to build up; cages are better, but keep them away from all drafts. And you cannot keep rats in direct sunlight- they overheat very quickly and can die. Keep them in a dim room whose temperature never gets above 80 degrees.
Rats are incredibly intelligent and friendly, and they seldom bite, although like any animal, if they’re scared or angry, you just never know. Don’t get into the habit of giving them treats through the cage wire or sticking your finger through the cage wire- this leads to biting behavior. But some rats will nibble you lightly in a friendly, grooming way, and also lick you- this means you are a good friend, so be flattered.
Don’t give them cheese- it causes diarrhea, as do all dairy products. Some people say a little is okay, but I like to be on the safe side. Don’t give them anything gummy or chewy, like carmel or gum- they’ll choke on it. And no soda! Rats love it, a lick or two off your finger every once in a while is okay, but no more- rats can bloat badly from the carbonation. (They can’t burp, either.)
Males do smell a bit more than females- if you change the bedding more often, you won’t have any problems. They may fight enough to have to be seperated. Or, you can actually have your males neutered by a vet. This ends the fighting and the smell, and it also decreases the risk of prostate cancer. It also means you can keep females with them.
Absolutely no phenols- ratty respiratory systems can’t take it. Don’t even use phenol-containing cleaning products. I use a great disinfectant/bactericide/viricide/fungicide combo for all my animals, reptiles included- it’s called Quat Plus and yu can get it here.
Best of luck to you and your new ratty friends- give them a kiss for me. Keep us posted, and link to pictures if you’ve got 'em. 