Yeah, chickens just have a lot of bones and connective tissue which dissolves somewhat during cooking. That’s the sticky part. You don’t notice this with beef or pork because we rarely handle an entire carcass at once like we do with birds. Also the meat/fat to bone/ligament ratio is much lower in chickens than in cattle or hogs. Hog and cattle carcasses are used to make gelatin so we know they get sticky too.
Try cooking up a boneless chicken breast and see if it’s as sticky as a whole bird.