Bird sanctuary foreign to herons (3,5)

I believe the answer is:

hen roost

I'm a little stuck... Click here to teach me more about this clue!

'bird sanctuary' is the definition.
I know nothing about this answer so I can't judge whether this works.

'foreign to herons' is the wordplay.
'foreign' indicates anagramming the letters (foreign order of the letters).
'to'+'herons'='toherons'
'toherons' is an anagram of 'HEN-ROOST'.

Can you help me to learn more?

(Another definition for hen roost that I've seen is " Where some layers sit".)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.