Re Chickens And Other Fowl
Any decent rabbi or Talmudic scholar will tell you that technically it is acceptable to eat chicken with dairy products. However, a long Jewish tradition (tra-dit-ion!) prohibits it. It’s easier to seperate all meat from dairy products than to seperate some meats from dairy products. Not eating fowl with dairy also prevents the possibility of mistaking a prohibited hamburger with cheese for an allowed turkeyburger with cheese and eating a forbidden food.
Back To The OP
I can’t remember which sage said “It is better to believe and not keep the commandments, than to keep the commandments and not believe.”