Chapter 1 contains Old Major's speech to the animals.  Several parts of his speech are oddly specific about things the animals should do or shouldn't do as well as what is evil vs. good.  Many of the things that he specifically mentions are the exact things that the pigs later adopt in the novel.  

Chapter 2 reiterates Old Major's speech when the animals create "The Seven Commandments."  Orwell uses that repetition to further emphasize their future importance to the reader.  

THE SEVEN COMMANDMENTS 1. Whatever goes upon two legs is an enemy. 2. Whatever goes upon four legs, or has wings, is a friend. 3. No animal shall wear clothes. 4. No animal shall sleep in a bed. 5. No animal shall drink alcohol. 6. No animal shall kill any other animal. 7. All animals are equal.

At the end of chapter two, the animals are wondering what to do with the 5 buckets of milk just gotten from the cows.  Napoleon tells the animals not to worry about it and sends them on their way.  When the animals return, the milk has disappeared, which foreshadows that Napoleon is a sneaky and cunning individual who should not be trusted. 

Chapter 3 contains these lines:

"Here the work of the coming week was planned out and resolutions were put forward and debated. It was always the pigs who put forward the resolutions. The other animals understood how to vote, but could never think of any resolutions of their own."

Those three sentences foreshadow to the reader how the pigs are going to harness all of the power and lord it over the rest of the animals.  They have already begun to run the rudimentary government and are going to continue to further strengthen their position.