How exactly is poultry a grey area? Have you met birds before?

I have, they are capable of feeling pain and possess reasonable intelligence. I just don't consider them sapient in a way that matters. If you cut off a chicken's head, it will still act like a chicken. This implies that most of what a chicken feels mentally is instinctual. If you cut off my head and I came into work the next day acting normal, it would raise serious questions about the nature of human consciousness. Poultry shouldn't suffer unnecessarily, but I doubt it has much sapience. Thus a gray area depending on how you judge their intelligence and your own morals.

I hear what you're saying about oysters (even though I disagree)

Vegans always say that but not a single person has ever responded to that point in my 6 years of making it. If you disagree, do what the vegans I've talked with failed to do and address it please.

making the same case for fish/octopus

You shouldn't eat octopus. Everything I said about poultry applies 3 fold to fish. Less capacity to feel pain and less sapience. I don't consider a creature that acts entirely on instinct to have any right to life.