Where do the rats learn about stockpiling in mrs Frisby and the Rats of NIMH?

In "Mrs. Frisby and the Rats of NIMH," the rats learn about stockpiling from the human farmer, Mr. Fitzgibbon. They observe him storing food for the winter and realize they can do the same to ensure their survival. By watching and learning from humans, the rats are able to apply this concept of stockpiling to their own situation in the rose bush.