No problem, I totally understand where you guys are getting that gut feeling, and a good breeder should be able to show you pictures of the rest of the flock, maybe video, and explain the condition of any birds being sold if they are in less than top condition when they are sold.
These 2 cases...
For what it's worth, a seller asking to meet you somewhere other than their farm to sell birds is not a bad thing or a sign of someone being shady. Proper bio-security means that no one that has birds of their own goes anywhere near your birds and someone that is buying birds likely already has...