Mix soy sauce,worcestershire sauce,balsamic vinegar,sugar,pepper,and onion together. stir until sugar is disolved set aside. With chicken thawed,remove innards, rinse and pat dry. Take said bird put it in ziploc bag,pour in marinade,seal put sealed bag in 2nd ziploc bag (in case of leaks)marinate overnight. give chicken a turn when you think about it.Take foil and wrap soda cans place in bottom of crock pot. pour marinade in bottom of crock pot(i just pour it all in)place chicken on top of cans, cook about 8 hrs on low. I cook mine until the wing joint pops out,usually abt 8 hrs and its falling apart. Enjoy, I serve it with stuffing.