If you happen to eat bad chicken you can get food poisoning or simple stomach pain and diarrhea, vomiting etc.
When chicken is bad it will usually have a bad smell to it or become a different color and have a bad taste.
If you cook the chicken and it tastes bad or smells bad then throw it out because it's not worth the risk of getting sick from it.
The cooking of the chicken helps to kill bacteria such as Salmonella but you still can get sick from other bacteria in the chicken.
You'll usually notice a foul smell that will make you vomit when the chicken is raw and bad and you would not want to eat it.
If the chicken is cooked and it goes bad it will also have a bad taste to it and may also have mold growth on the chicken.
Raw chicken will last around 2 to 3 days in the refrigerator and around 6 months to a year in the freezer.
Cooked chicken usually lasts 3 to 7 days in the refrigerator and when frozen can last from 6 months to a year.