✅ SOLVED Warmer for what?

[invent4hir]

All, I returned to the former chicken farm yesterday and dug these 2 brass round objects. They both measure 3" in diameter and the one on the right is about 1/2" tall, because it has some sort of fitting. The one on the left has the word "WARMER" near the center. Looking at the third picture it appears they are formed by 2 thin disks sandwiched together. Can anyone ID and/or date these?

 

[HuntinDog]

Being from a chicken farm they may be nest warmers.
Although I don't really think that is what they are.
I've seen them before but CRS keeps me from remembering.

 

[creskol]

It is a "thermostat wafer" used in brooders and incubators.

 

[invent4hir]

Creskol, man you are good! I thought it could be chicken related, but because I found a 1928-29 Ford Model A radiator cap and early 19th C fiddleback spoon in the same area, I wasn't sure. Again thanks so much, the property owner is a history enthusiast and will happy to know the ID.

 

[A2coins]

Good id

 

[Reanm8er]

Also known as a barometric can!