I've found a very strange sentence today.

VOA report

…………This was especially true in the southwestern states of Oklahoma and Texas. Farmers there were losing money because of falling prices for their crops. Then natural disaster struck. …………

Why not "Farmers in there……"?

there means at that place, so

farmers there means farmers at that place or farmers who were there or farmers who were at that place.

There's nothing unusual in this expression.

People here use it all the time!

This is fine and common mid-position of an adverb (there) SAV
Students: We have free audio pronunciation exercises.
Flora Tang Why not "Farmers in there……"?
"Farmers there" is very common.

"there"=in/at that place
"in" or "to" is inherent in "there.
 CalifJim's reply was promoted to an answer.
Students: Are you brave enough to let our tutors analyse your pronunciation?