I love making stock! My stock gels so hard it barely jiggles when you bump it. I had to learn because my whole family has horrible joints, but the pain of damaged joints has reduced since we started eating "bone broth".
Gelatin comes from connective tissues (collagen), and is not damaged by boiling. The worst you'll do when you boil stock is make it cloudy. Not exactly earth-shattering. The part of the chicken that has the most of collagen is tendons and cartiledge, especially found in the wings. So cook your chickens for dinner and enjoy the meat, then save every part you don't eat. Bones, skin, neck, back, wings, yep, all of that. If you don't have any leftover chicken carcasses hanging around you can pick up some wings quite cheaply. Throw all the chicken bits in the slow cooker with your aromatics (onion, garlic, celery, carrot) and herbs and spices (pepper, bay leaf, herbs), smack everything as flat as possible and add just enough water to just barely cover it. Then crank it to high, then down to low once it simmers, and go do something else for 3-6 hours. Strain, cool, and you're done.
Here, I do so adore Alton Brown:
http://www.youtube.com/watch?v=531v0T_LD1E