Full digestion of foods such as chicken is around 24 to 33 hours depending on how much chicken or other meats that you've eaten.
However if you just eat a few pieces of chicken then the chicken should be digested by your stomach acid within 2 to 3 hours.
But even though your stomach acid has digested the chicken it can take several hours longer before the chicken or any other meat has been able to pass through your stomach, intestines and colon before you poop out the waste.
Your body uses the chicken and other foods to give you energy and whatever is leftover as waste then gets passed through your intestines and then your colon and then out your rear end.