Don't believe everything that a vendor tells you. He is in the business of selling and has no problem telling a prospective customer what he believes they want to hear.
OT but this applies even more so with guinea fowl. No other poultry have the same manners as guinea fowl and no other poultry can understand the behavior of guinea fowl. Turkeys fall into the same category but their manners are more understandable by other poultry.