How did the changes of the commandments come about and why? How does the change in the commandments affect the individual animals on the farm?
The seven commandments of Animalism, are the simplification of the philosophy of Animalism itself. They are changed secretly to aid the pigs in their hunger for power. The other animals have no idea that this is going on, but when they do realise, it is already too late because the pigs have gained all the power. The change in the commandments affect each of the animals individually. Some are too gullible, and so don't realise it, while others are shocked and terrified of the pigs.
Originally, the pigs followed and obeyed the commandments, but slowly they became corrupted by the power, and modified them to their advantage, justifying their comforts thus: "And very comfortable beds they are too! But not more comfortable than we need, I can tell you comrades, with all the brainwork we have to do nowadaysÃ¢ÂÂ¦You would not have us too tired to carry out our duties? Surely none of you wishes to see Jones back?" The pigs are exploiting their power contravening the commandment "no animal is to sleep in a bed", the pigs simply change it by adding "with sheets" to the end of it.
Some of the smarter animals are slightly suspicious of this, but Squealer convinces them with propaganda, and citing the authority of Napoleon.
Squealer uses rhetorical questions to gain their acquiescence: "Surely none of you wishes to see Jones back?" It also immerses the animals in on a personal level so that they think that this is all being done for them and they should be grateful.
The pigs had a lust for power, so for them to gain more control without the animals noticing,