I've made and fitted these a few times, Jayne. Quite a simple job.
I guess you mean a "roof" conversion ... no birds involved ;o)
The biggest issue is where to "park" them when they're open. For a, say, 4' (1200mm) wide window, a 2' shutter might stick out into the room too much (one pair of 2' shutters.) In which case, they could be "bi-fold". i.e. each shutter is split into 2 x 1' shutters. They can then fold back on themselves so that they only stick out 1' into the room.
Lots of permutations. I'd need more info... perhaps a pic?