fowl paranoia

normally i'm pretty good about my food paranoia. {i have real issues with ground meat and the like} But it never dawned on me that chicken gizzards could come from other chickens. How do I know that the lungs, liver, neck and heart actually came from the chicken I just defrosted? I didn't kill this chicken. Either I'm crazy and they DO come from the same chicken, or my chicken today was some supreme being and had 2 hearts...
gross.