Terms such as "Show Quality" or "Heritage" are very generic and shouldn't be taken with much weight. Essentially, "Show Quality" means that the bird doesn't have disqualifications, it doesn't mean that it is a half decent specimen. Many people claim and assume that their birds are show quality.
Any breeder truly breeding with the SOP knows that most birds are show quality, but very few are worthy of breeding and showing. Therefore, they generally use terms that are less promising (but are actually more promising for shoppers if they know to look for them). These terms would include Standard Bred, Show Potential, and Exhibition Strain or Bloodline.
Only, if purchasing an adult fowl, would the term Show Quality apply. But, once again I would prefer proven show winner, or excellent potential in the birds description.
The best thing you can do is research. Know the breed, as well as you can, before you buy. Pictures aren't great, but they can display the obvious often enough. Just the other day, I saw someone asking a lady if her BLR Wyandottes were show quality. To which she responded, 'Yes." The birds in the photographs were far from the standard, one had a single comb, and most had pinched tails held at the wrong angle. But, both breeder and questioner were obviously none the wiser.
Also, do research on breeders. Don't buy anything quickly, look around, see what people are saying.
