Museum had to be given slats for ventilation (7)
I believe the answer is:
louvred
'slats for ventilation' is the definition.
I can't tell whether this defines the answer.
'museum had to be given' is the wordplay.
'museum' becomes 'louvre' (art museum in Paris).
'had' becomes 'd' (in contractions e.g. 'I'd', 'you'd' etc).
'to be given' says to put letters next to each other.
'louvre'+'d'='LOUVRED'
Can you help me to learn more?
(Other definitions for louvred that I've seen before include "Like some doors" , "provided with overlapping slats" , "(Of a shutter) slatted" .)