Since I have found it hard deciding the stages of rat estrus cycle, I would like to share my experience on it. Thus please refer these pictures for different stages of rat estrus cycle through the pictures I have taken. The text for the explanation of these stages can be found elsewhere, but the pictures are confusing. I have tried my best to post precise pictures at various stages.
1) Diestrus Stage:
Small dots are leukocytes.
2) Proestrus Stage:
3) Estrus Stage:
4) Metestrus Stage: