Repeat that they were fed after their nap (7)
I believe the answer is:
restate
'repeat' is the definition.
(I know that repeat can be written as restate)
'they were fed after their nap' is the wordplay.
I cannot quite see how this works, but
'fed' could be 'ate' ('eat' can be a synonym of 'feed') and 'ate' is found within the answer.
'nap' could be 'rest' (I've seen this in another clue) and 'rest' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
'that' acts as a link.
Can you help me to learn more?
(Other definitions for restate that I've seen before include "say, a different way" , "Go over" , "Once more affirm" , "say, in other words" .)