After boiling a chicken for soup and straining with a fat separator, how much fat is left in the chicken? Does it depend on how long I boil the chicken for?
Yes, it depends on how long you cook the chicken. Much of the fat is in the skin and can be removed by peeling it; other fat (such as in the thighs) tends to stick around. Long, slow cooking will render more of the fat, which melts at around 95° F.
I'm guessing you're trying to avoid fat for dietary reasons, but consider saving it for future cooking purposes - like where you might use another oil. It's delicious, and not terribly harmful in small quantities.
I agree, a fair amount of fat tends to remain in the skin. Evidence for this: to make soup, I boil a whole chicken for 2-3 hours, then cool and pull off the meat. Usually I peel off the skin and fry till crisp in a pan. It doesn't produce as much fat as bacon, but more fat than you would think.