I have been cooking chicken in crock pot for 7 hours and it's a bit pink. is this okay?

I've been cooking 4 large chicken in a crock pot on low for 7 hours, but they are still a bit pink inside. i don't have a meat thermometer. Been meaning to get one. cooking them this long, it seems like they should be done. Is any amount of pink okay? Is it different in the crock pot somehow?