Just get a heat lamp, and don't worry.
Indeed.
Yes, a heat lamp can be a fire hazard -- if it's poorly secured or used in a too-confined space. ANY electrical item is a fire hazard in a chicken coop to a greater or lesser degree.
But many people use heat lamps successfully -- firmly secured by a wire or chain in a roomy brooder and the alternatives may not provide sufficient heat in an outdoor brooder when the ambient temperature is too low.