That’s dried on membrane. I wouldn’t wash a chick, you risk chilling them and cause more issues. I know people do it, but it’s a risk they’re willing to take.This is the thing. I think it might be the yolk sac, but isn't it supposed to be already absorbed since the blood was? I'm very confused. The chick is kicking and trying to get away, it looks frustrated
You can use any oil you want. Olive oil will be fine.