The most common and most likely answer to this crossword clue is the 8 letter word FEEDLOTS
F
E
E
D
L
O
T
S
More clues leading to the result FEEDLOTS
Buddy explains!

The straight part
We know that "plots where livestock are fattened" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case plots where livestock are fattened = feedlots.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does FEEDLOTS mean?
FEEDLOTS noun- Land on which livestock are fattened for market.