It's about 50F and rainy today, it should be 48F tonight. The chicks leave the brooder to walk around, chase each other, preen, scratch and peck, eat and drink, then return to the brooder to snuggle and nap, so it seems to be working okay without additional ambient heat.
The manufacturer of the brooder plates doesn't say anything about operating in temps <50F so I'm assuming they'll be okay. I'll keep an eye on them, we also have a camera on them since they're outside.
No chicks were shipped, they were all local and I picked them up.
Our brooder plates have "comfort feathers" to help them seem a little more like mama. The chicks love them.
I read somewhere that brooder plates don't operate as well when outdoor temp drops into the 40s. I couldn't figure out why that might be, though.
Our nighttime temps are in the 40s and 50s. The brooder has two 10"x10" brooder plates for 15 chicks.
Does it also need an ambient heat lamp at night for new chicks (one and two days old)?