We try to keep our rats on a low fat, grain heavy diet - like is because overweight rats can have significant health issues, especially later in life.
We don't add tasty things like banana chips, dried fruit (except the occasional cranberry), coconut or almonds as we found our rats picked these out first and just scoffed them over the healthier options.
Our standard dry mix consists of:
Cereals:
Kornies
Corn flakes
Rice bubbles
Wheatbix
Wholegrain oats
San Bran
Bran Flakes
Grains:
Barley Flakes
Wheat
Hulled Buckwheat
Kibbled Wheat
Rye Flakes
Brown rice
Barley
Green split peas
Red lentils
Brown lentils
Puffed spelt
Seeds & dried fruit:
Pumpkin seeds
Linseeds
Sunflower seeds
I try to keep the seed portion of the dry mix very minimal, with exception to the linseeds which are rich in omega 3 fats and folic acids so are beneficial in their diet.
We will also be adding dehydrated foraged plants like:
Puha (Sow Thistle)
Dandelion
Plantain
Nasturtium
Hibiscus
Basil
A good quality pellet should be a rats staple diet. We personally feed about 70% pellets and a 30% dry mix. They're not as tasty as a dry mix, but are all super nutritious.
From pet-shops like Animates, you can pick up:
Supreme Selective/Science Selective
Vetafarm Origins
Online shops:
NZ Rat Rescue lab blocks
For large quantities (10kg +) you can go to Feed shops, like Sharpes or Horselands and get:
Sharpes Diet 86
NRM Pig Nuts
This works out really cost effective if you have a good number of rats.
We've compiled an extensive list of rat safe & unsafe foods. If in doubt, check Google or in rat groups on facebook for a second opinion.