In chapter ten of Animal Farm, the pigs start walking on two legs. Explain if this is a sign of progress?

The transition from four legs to two legs could be
considered both progression as well as regression. If you look at it from the
perspective of the pigs, then it absolutely is progress.  It is an important stage in
their transformation (specifically Napoleon) into the similar figure of a human-like
dictator that once tyrannically, callously, and with self-indulgence, governed the farm
(allegorically connected to Stalin’s evolution into a tyrannical leader after the
overthrow of the tsar, Nicholas II of Russia). Orwell does an excellent job
demonstrating this correlation when he creates a revelation with the “other” animal
characters that Napoleon (and the other pigs) is now discernable from the other humans
in the room. By the end of Orwell’s novella, the pigs had effectively moved into the
role of a self-serving government whose “progress” on the farm was founded upon not only
the exploitation of the lesser, and significantly less intelligent, animals, but also on
the use of manipulation tactics aimed at keeping the exploited animals subservient
through menial labor, lack of rights and the removal of their
voices.

However, if you consider this question from the
alternate angle of the farm animals, then it is a regressive action. The non-pig animals
begin with a hope and dream of utopia through socialism only to have it destroyed by the
manipulative and malevolent methods of self-serving “comrades.” For example, due to
their lack of intelligence—evident in their continuous inability to recognize the
changing rules, the shift in labor and the special allowances being extended to only the
pigs— they remain in a subservient role until it is too late. This allows Napoleon’s
transition to take place, along with the other pigs. Many of them don’t even recognize
the atrocity of Boxer’s murder as an indicator; in contrast, most of them continue to
follow the glittering rhetoric provided by Snowball as he contorts the truth to comfort
them. So, the pig’s transition from four legs to two legs could actually be considered
symbolic of regression as it relates to the destruction of the socialistic ideal
initially glorified by Old Major at the beginning. In addition, the transformation from
four legs to two legs also substantiates Orwell’s theme of corrupt governmental
institutions finding success through the disenfranchisement of its
‘people.’