But that's not the survey they used. A search on Mintel reveals surveys on pet ownership that seem targeted for consumer research and pet industry (eg:
https://store.mintel.com/americas-pet-owners-us-august-2018 and
https://store.mintel.com/us-americas-pet-owners-market-repor...).
Their methodology as outlined on their web site (https://store.mintel.com/mintel-methodology) and details the quotas they utilize to get what they feel is a statistically relevant cross section of data.
Anytime sampling is used, of course it's not going to be exact. But a 2000 person survey is, given equal statistical rigor, going to be better than a 500 person online survey and might be enough of a population to justify more detail.
(Unfortunately, the Mintel survey results cost $4300, so other than their methodology page it's going to be difficult for me to infer much more. But the methodology page seems to suggest they aim for +/-2 or 3% confidence level.)
