I'm not quite sure to be honest, because we have a wood stove, and I'm not quite sure what temps it does.
The chicken goes in the bottom of the oven, with a tray over the top, so maybe it's more that it keeps it moist then the actual temp.
At that age they make the best roasters, imo. Just make sure to cook it pretty slow. And definitely keep it in the fridge for at least 2 days, but can go for up to 5.
And you're making the right choice, never mind how hard it is :hugs