These all my impressions, do not take them as gospel.

-----------------------
They also contain corn which most often contains fungus and mold, tiny seeds which are not eaten (some of my rats eat them) and also alfalfa pellets which are hard for a little rats stomach to digest.
I don't think you need to have stomach at the end, it should be understood
"... hard for little rats to digest.
---------------------------
misspelled
This kind of food gives them the complete nutrition a rat needs and also helps keep their teeth from becoming overgrown.
---------------------------
I don't think you need both terms
You should be able to find them in most pet stores, feed stores and sometimes also through breeders, as well as online.
maybe leave out also
You should be able to find them in most pet stores, feed stores and sometimes through breeders, as well as online.
---------------------------
misspelled
Some good brands to consider are Harland Teklad (http://www.teklad.com/), Purina and Mazuri brand lab blocks.
----------------------------