I have been looking everywhere and cannot find an answer. Question: can I use a natural gas ventless/vent-free heater in the same room as the parrot are located? The room is about 20’ x 20’ with vaulted ceilings. Where the parrots are located in the family room, it is cooler than the rest of the house. I would prefer to use a gas heater in lieu of larger electric heaters to take some of the chill out of the air. I do have small forced air electric heaters that I run at night and cover the tops of their cages to keep the heat in. I live in northeast Ohio and the cold winter months are fast approaching. I plan to have a O2 and CO2 sensor within the room to monitor the air quality. Thank in advance for any and all comments.