With pet rats, most aging symptoms are similar to those of humans. And as with people, it takes caring and patience to assist your dear rattie through her last stage of life.
The best preparation is to know what to expect. For example, old rats have the tendency to develop incontinence, urinating all over themselves. All you can really do is give them frequent baths. Otherwise, their fur will have a yellow tint and foul smell. Also, their bones and teeth can become sore; so be sure to lay down extra soft bedding and feed them soft, water-rich foods.
Putting fruits and veggies through a juicer is a great way to continue feeding them. Put the juice into their water bottle along with ice chips to keep it fresh longer. At that point, stop feeding them lab blocks.
When arranging the furniture, adapt the living environment to their abilities. Once rats get old, they are no longer able to run, climb and jump as they used to; nor are they able to recover from injuries as easily. Be sensitive to this and make their cage as safe as possible by lowering all their platforms and making their food and water available lower.
As rats age, it gets more difficult for their bodies to regulate their temperatures. That means they will be most prone to hypothermia in the winter and overheating in the summer. To keep them warm, in extremely cold weather place a heating pad or electric blanket below (not inside!) their cage. Ice cubes and a powerful fan (placed far away) can help cool an elderly rat during a heat wave.
There are other tell-tale signs of rat-aging. Once their appetites decrease, they