quote:
"...the Question 3 ballot initiative that passed by 78 percent --
which is not only the single largest margin of any ballot initiative law
ever passed in Massachusetts,
but also the highest margin of victory for any animal protection measure
passed by ballot initiative in this country --

[for example,] activists tried to pass that very same measure
through the traditional means in the Massachusetts legislature
for eight years straight,
and it kept getting stymied by agricultural committees.
[ . . . ]
Trying to get any new law passed at the federal or state level
that protects animals raised for food
is very difficult,
because each of them
has to first be approved by an agriculture committee
that is usually staffed with
those who are sympathetic to agribusiness. "   endquote

Here's the whole article.
interview with Executive Director Christopher Green, Animal Law & Policy Program, Harvard [university] Law School