In Chester he accommodated a flightless bird (4)
I believe the answer is:
Here is my best explanation:
'a flightless bird' is the definition.
(rhea is a kind of flightless bird)
'in chester he accommodated' is the subsidiary indication.
'in' indicates the answer is hidden within the clue.
'rhea' is hidden in the letters of 'chester he accommodated'.
(Other definitions for rhea that I've seen before include "Flightless South American bird", "S American runner", "Bird resembling ostrich", "Flightless bird -- satellite of Saturn", "nonflyer", "Moon", "Small 'ostrich'", "Flightless bird from South America", "Titaness" and "China grass".)