What events in this section of the novel suggest that the pigs no longer believe the Seventh Commandment, "All animals are equal"?

This is with reference to the Seven Commandments set down
by the animals on ‘Manor Farm’ when the animals revolted against Mr.Jones and all other
care–takers and ousted them from the farm. They all had a meeting and under the
leadership of the pigs laid down the ‘Seven Commandments’ the seventh one being the one
motioned above. All was well in the beginning as every animal strictly aderhed to these
‘Seven Commandments’ and the farm was run on egalitarian principles in course of time
the pigs themselves become corrupted by power and they established a new tyranny under
their leader Napoleon. Gradually jealousy deceit, greed for power, corruption, ruination
crept into the lives of the pigs who gradually betrayed the ‘Seven Commandments’. They
violated them from time to time and even changed these commandments to Justify and suit
their wrong doings. Things got worse on the farm and the other animals wondered if their
days were better then during the time of Mr.Jones or now under the leadership of the
pigs. Soon they saw the pigs walk on hind legs all carrying whips in their trotters
supervising the work of other animals and chiding them if they did not rise to their
(the pigs) expectations. The pigs bought themselves a wireless set, contributed to news
papers like the ‘Daily Mirror’ educated themselves while the other animals toiled on the
farm and slept on cold straw beds hungry, while all the time the pigs ate, made merry
drank, sang and slept on beds with sheets Seeing and sensing the deteriorating situation
the sheep began to sing ‘Four legs good two legs better!. All the animals in shocked
silence went to read the wall on which the ‘Seven Commandments’ were written and to
their dismay they saw that their was nothing there now except a single Commandment ‘All
animals are equal but some animals are more equal than the others. After this they did
not feel strange at all at the treatment meeted out to them by the pigs headed by
Napoleon.