I've seen 'Creature Comforts' a couple of times on TV, and both times it's been in the form of (what seemed to me anyway) about a half hour short, where the 'interviews' would cut back and forth between the different animals. Imdb gives it a running time of 5 minutes though, so I wonder whether what I saw wasn't compiled from various shorter films.
In any case this was the first time Aardman and Nick Park came to public attention. The idea is a series of interviews with zoo animals who talk about their living conditions, are they happy, and so forth. The actual dialogue though is unscripted, apparently recorded impromptu during interviews with people in nursing homes, etc. Pretty obviously this gives it an edge of social commentary and satire which is notably absent from the later works. Compared with 'Wallace and Gromit' it's actually rather slow and serious.
To be honest I found it more clever than funny. The claymation certainly isn't up to standard which Park would achieve with the W&G shorts either. It's still definately worth chasing up, though. I wouldn't mind seeing it again.