Go to Lowes, purchase a heat lamp, put a tarp around the lamp like a little tent and instant heat. It keeps chicks and such warm.
They sell them with the clamp on type funnel shaped holder. The lamps are good for 5000 hours. Easy to set up easy to take down.
https://www.lowes.com/pd/Woods-300-W...ard/5000375623
https://www.lowes.com/pd/GE-250-Watt...ulb/1000438359