I would be the "kid". I'm 23 now but in grad school so I have less breaks and less time off during those breaks...
BUT whenever I have gone home in the past during college my parents never made me pay for anything. I worked for my dad when I could (he owns his own business and paid me when I did work) and during my freshman and sophomore year breaks I worked retail. This was more for my own spending money than anything else. If I went out to eat w/ friends during breaks or needed to buy gas, or had to pick up some milk on my way home, sure- I'd pay for it.
I am not "forced" to do chores (never really have been) but I do clean the entire downstairs of our house at least once during my stay (my dad's a workaholic and my mom works full time and doesn't have the energy or motivation to clean). And I of course will shovel the driveway if need be, or do the dishes, cook, vacuum, etc. These things have always been more of me wanting to help my parents out rather than being forced to.
Not a single one of my friends has ever been required to buy food or help with bills on BREAKS from college. A few that have moved home after graduating have been required to help out and I find that totally understandable.
I just think it's unreasonable to have a college kid help out with the electricity bill when they are home for a few weeks. I'd rather not go home and find a way to pay for my own place if my parents were going to be that petty.
Helping out around the house is one thing, but chipping in for bills is another.