You will need a large crock pot for this. If you have a smaller one then instead of a whole chicken then use a cut up chicken and fit what you can int the pot.
Slice one onion layer on bottom of lightly oiled crockpot
clean and rinse one whole (I use free range) chicken
Place on top of onions
squeeze 1 to 2 lemons over the whole chicken
Create a rub
I have two that I like.
One is paprika, chipolte pepper spice (you can sub any nice peppery spice here like cajun spice or chilli spice or …)
rub all over chicken.
The other rub I like:
I again squeeze 1-2 lemons over the chicken
coat the chicken in a think layer of honey
mince up fresh ginger, garlic and sprinkle over the whole chicken
Cook on High for 4-5 hours or low for 6+ hours depending on the size of the bird, for cut up chicken probably less time. You can tell the chicken is done as the wings start pulling away from the bird. I like to put the bird in breast side down back side up.