Mine are in cages for one simple reason, the only complaint I have ever
had from the neighbours downstairs was in 7 years was Felix related.  I
was away one night and left him to have the run of the room.  The next
evening I had a vist from downstairs to complain about the noise as Felix
had spent the whole night chasing an airflight golf ball round and round
the room.
 
Tony and The Fabulous Ferrets Of Chaos
[Posted in FML issue 3602]