'Im seeing so many posts from breeders and pet owners about the use of chicken brooders as a heat source. It really kills me to see people recommending them and felt the need to explain why I personally do not recommend them.
Hedgehogs need their ambient temperature to be between 72-80 degrees. Ideally, I like to keep mine at 75-80 degrees. Hedgehogs in captivity cannot hibernate properly. If a pet hedgehog's ambient temp (meaning their air temperature) gets below the recommended range, they can attempt hibernation. If a hibernation attempt is left untreated, it will be fatal to your hedgehog. This is why we require certain heat sources to keep our prickly pets toasty and warm.
I have a Brinsea Ecoglow brand chick brooder. Its not a cheapo brand, its one of the top brands of chicken brooders. I have the Brinsea 20, which means its suitable for up to 20 chicks. I have used it with chicks and had great success. The way the brooder works is that the chicks crawl under the brooder and push their backs against the heat plate to warm up. Chicks need to move to the heat source when they are chilly so that they can warm up. While it may minimally heat up the ambient temperature directly under the heat plate, it definitely doesn't heat up the ambient temp of the entire cage, and therefor would be useless for use with a hedgehog. A hedgehog wont stay directly under the brooder at all times. They are nocturnal and will roam their cage and run on their wheel most of the night which makes a brooder an unsuitable heat source for a hedgehog.
I think every breeder can agree that a reptile heating pad can cause severe burns on hedgehogs and aren't recommended. When using a heating pad with a hedgehog, it will not warm the ambient temperature enough. When the hedgehog gets cold, it will retreat to the heating pad and wont move until its completely warm, which can result in serious burns. If the ambient temperature of the entire cage is kept at the appropriate temperature, the hedgehog wont need to retreat to an area to warm up, which means it wont ever attempt hibernation. The same goes for a chicken brooder. A chicken brooder works the same way as a heating pad, the animal must be touching the brooder to get warm.
A heating pad like the zoo med under the tank heater (popular, well known brand) gets approximately 105-110 degrees. As stated above, heat pads can cause severe burns in hedgehogs. They can also cause severe burns in snakes if there isn't a thermostat to regulate the temperature, but hedgehogs need AMBIENT temperature.
I did my own little test and brought in my Brinsea chick brooder to test the temperature difference of the brooder vs a heating pad (reminder that a heating pad is known to cause burns in hedgehogs). If I hold my hand against the brooder plate, it eventually gets too hot for my hand to comfortably stand the heat. Using a infrared thermometer, my brooder is at 119.4 degrees which is significantly higher in temp than a heating pad, which is known to cause burns.
Since brooders do not raise the ambient temperature of the whole cage (like a ceramic heat emitter or an entire room that is heated to the appropriate temperature) they are not a sufficient heat source for a hedgehog. When you also add in the fact that these brooders get quite a bit hotter than a heating pad, its quite obvious that these are dangerous and should only be used for their intended purpose- chickens.
The only heat sources that are safe for a hedgehog is a ceramic heat emitter hooked to a thermostat set to the required temperature or to heat an entire room with a space heater with a digital thermostat.
I understand that heat emitters can seem like a fire risk. They do get hot to the touch! That's why its extremely important that emitters be secured in place and be plugged into a thermostat. Rooms heated with space heaters can be equally dangerous if not properly used. That doesn't make a brooder an appropriate heat source for a hedgehog.