"So they eat chicken?"
Translation:Mereka jadi makan ayam?
Jadi can also mean "thus" or "for that reason", so "mereka jadi makan ayam" could mean "they thus ate chicken" e.g. "Restoran tidak punya daging sapi (beef). Mereka jadi makan ayam". It could be translated with "so" but "thus" helps you see why it doesn't have to go at the beginning. At least I think that's the case.