There are three commandments broken in these chapters:
1. Whatever goes upon two legs is an enemy.
4. No animal shall sleep in a bed.
7. No animal shall kill any other animal.
Engaging in trade with Whymper breaks the first commandment because he has two legs. The pigs argue this had to be done in order to provide the animals with necessary items like dog biscuits, iron for horse shoes, paraffin oil, and eventually food for the animals, their farm wasn't going to provide it all.
They changed the 4th commandment to
No animal shall sleep in a bed with sheets.
They argued this one away by stating that the beds provided a minimum amount of comfort necessary for them to complete their brain work. They also pointed out how ridiculous it would be if the commandment had been that animals couldn't sleep in beds because even a bunch of straw is a bed.
Finally, in chapter 7, animals believe (although it isn't true) that they have been in cooperation with Snowball, for which the price is now apparently death. No pig really offered any discussion after this with any reason, they just left.
In the book "Animal Farm" the animals have created new commandments so that they could do away with the way humans act and have treated them. One of the commandments is that no one shall sleep in a bed. The pigs break this commandment by sleeping in the beds. They have taken residence in the farmhouse under the explanation that it is necessary that the pigs, who are the brains behind the operation, need a quiet place to be able to think. In addition, they had taken the sheets off of the bed.
The other broken commandment was that they had arranged to work with a human being who would act a a go between. The animals are initially lied to by Napoleon who tells them that no contract had been entered into so no commandment had been broken.