I visited a Cairn Terrier breeder who claimed a dog for sale, 1.5 years, was a retired and trained show dog. The dog does not respond to the word sit and pulls on the leash while walking, even on short leash. Apparently the dog had walked for half an hour that day beforehand.
Is this expected behaviour?
It's quite common for show dogs not to be taught "sit": the thinking is that if you teach "sit", they learn that it's a normal behavior, and you don't ever want a dog to sit at the wrong moment in the show ring, like when the judge approaches the dog for the examination, or when they're taking the final look at all the dogs in the ring. (Some people teach "stand", since reinforcing a desired behavior can be easier than eliminating an undesired one.)
"Retired" means only that the owner has decided not to show the dog any more; it doesn't really imply anything about success or lack of it in the show ring.
With regards to the pulling, the show environment is going to be very different from what the dog is used to: strange location, lots of strange dogs around, possibly a strange human at the other end of the leash, possibly a different leash (show leashes tend to have a narrow thin collar so as not to interfere with the judge's view of the dog).
Anecdotal evidence for the last: I have a dog that would behave perfectly until the moment I stepped into the show ring, then would start pulling as strongly as he could, arching his back and choking just as the judge was getting their first impression of all the dogs. Another dog was perfect in the show ring on a show leash, but she's a chore to walk on her normal flat collar because she'll pull for the first 15 to 20 minutes before settling down.
