"Undercooked chicken" refers to chicken that has not been cooked enough and may still contain harmful bacteria or be pink on the inside. Full definition
You should have made sure that the chicken was fully cooked before serving it, because you know (or should know) that salmonella and other illnesses are a risk from undercooked chicken. (effectivecoverage.com)
«It often comes from eating undercooked chicken, because chickens can carry this bacteria in their gut but not get sick from it,» he says. (health.com)
I hear ya about being paranoid of undercooking chicken which is why I always overcook it and my poor children think they don't like chicken. (grumpyshoneybunch.com)