Or you could hypothesize that farming became popular for some
reason other
than the happiness of the farmers.
Having only encountered agricultural enterprises relatively late in
life, I found Orwell's choice of metaphor in Animal Farm very
precise; it goes well beyond "talking animals".
Consider the "problem of induction" faced by a pig[0]. Every day the
farmer comes to feed and take care of the pig ... up until the day
when the farmer comes, and the pig is slaughtered instead[1][2].
This outcome is certainly surprising based on the pig's experience up
until that point, but not surprising to anyone who considers that the
livestock on a farm serve (the farmer in particular, humans in
general) to convert things that people cannot eat into things they can.
Moving up a level, the farmer, for much of human history, served to
convert things that warlords cannot directly use, such as land and
livestock, into things they can, such as rations for armies and gold
for mercenaries.
-Dave
[0] we will leave aside the question of whether it is better to be a
pig satisfied than socrates dissatisifed...
[1] it has been suggested that one should avoid crossing pig farmers;
they are apparently have many ways to make bodies disappear!
[2] for much of human history, the warlords themselves faced a
similar problem: for most of their life, their society was set up to
serve them, up until the day when (preferably due to external enemies
than internal) they were slaughtered instead. modern warlords,
however, seem to have ditched the mores of the Iliad (or of the
Gita?) and prefer to let others do their dying.