At the end of "Small Tune . . ." there is a long shot of the back of Clegg's house and we get some voiceover chatter from the trio. In the shot you can see a cat in the back that looks like it belongs there and may (IIRC) be eating something by the back door. I always wondered if we were supposed to assume Clegg had a cat from that.
It is interesting how few pets the characters actually had in the series, or at least mentioned. Compo had his ferrets, of course, and Wally had pigeons and later the dog (who we never saw after Joe Gladwin died), but other than that nobody ever mentions them other then one episode were Ivy mentions having had a budgie.