Par-cooked chicken is done in the industry, but it is cooked to 150 degrees internal temp, just 15 degrees short of the recommended temperature for fully, safely cooked chicken. But htis practice is dying out because of the food safety issues. You can't see pathogens, so you never know how well you did killing them off with a par-cooked item. I would not mess with the idea, instead fully cook, then chill as quickly as possible. Food safety is not something to play around with. Re-heat later if you must.

Agree with the other judges. Bad idea.

Yeah, I agree with boulangere - it's really dangerous to half-cook meat, particularly since it allows the bacteria naturally found in raw meat to multiply rapidly due to warmth and cooking it later might not get rid of all of it...

It depends on what you are going to do with it during those 4-6 hours. What are your plans? It is crucial to cool it down to 70 degrees within 2 hours, then to 40 or below within 4 more hours. It might be easier - and safer - to roast it completely in one go.