Your chicken thighs will be ready to eat when they have reached an internal temperature of 165 degrees F. It’s okay if they get a bit above 165 degrees F though because, unlike white meat that dried out quickly, dark meat tends to be much more forgiving. Different sized thicknesses of thighs will cook at different rates so try to make sure that they’re flattened to about the same size so that they can all cook at a similar pace.