How cold can my chicks tolerate?

[Skylexa]

Our weather in TN can be very wild. It can go from 80°F days to 40°F nights very quickly.
Setting up a heating system in our coop is quite complicated, so we try to avoid heating as much as possible.
Currently, tonight, it's 54°F. Our chickens are about two and a half months old. We have three Barred Rocks, two Rhode Island Reds, and two Easter Eggers.
The coop itself is rather small (imagine a backyard chicken coop, not a building/barn).
There's a vent on the top layer of the coop and it has a cover. I cracked it to allow fresh air into the coop, but now I'm wondering if that was a bad idea since it's so cold out.

Any advice would be appreciated :>


EDIT: Thank y'all for the info! Your answers have helped me a lot!

Here's some pictures of the coop!
I know there's a few gaps in the doors and stuff we have yet to fix, but other than that the coop is pretty perfect for our needs.
The bungee cords are to hold the tarp in place so they can have a small rain cover over the run.

 

[Mellowmalt]

Those breeds are quite hardy. You will be fine. I stuck my dutch bantams out when it was 45 when they were around that age - they are about 5 times smaller and they did shiver but they did fine. Generally I would say watch how the birds behave, like I gave them heat to start with and after about a week they were perching away from it I turned it off but with your breeds I really would not worry about those temps, they should be able to handle them

 

[MissE]

54 is not cold for a chicken. Lack of ventilation is worse than cold.

 

[thehenandchick01234]

They should be fine it has be in the lower sixties in the part of TN that I live in so I don’t take them out as much. They r only 8 weeks old today

 

[MissE]

My 4 1/2 week old chicks are in an wire 4x4 dog ex pen in the barn. The waterer in the cold corner froze two days ago. The chicks were nowhere near the heat light in the opposite corner. They will be moved to an unheated tractor in the run for their introduction to the big chickens within the next week.

 

[aart]

The coop itself is rather small (imagine a backyard chicken coop, not a building/barn).

Post some pics?

40°F is nothing.....you won't even need to heat your waterer.

 

[3KillerBs]

My new, month-old chicks are doing fine with nighttime lows in the mid-40's the last few days. I just have to make sure they go into the coop instead of trying to sleep in the corner of the run exposed to all the elements.

https://www.backyardchickens.com/th...y-accomodations-for-the-new-arrivals.1466672/

Fully-feathered chickens can keep themselves warm and will suffer more from excess heat than from cold.

 

[Ridgerunner]

Our weather in TN can be very wild. It can go from 80°F days to 40°F nights very quickly.

I grew up in the Cumberland Gap area of Tennessee many decades ago. That weather sure can change in a hurry.

Our chickens are about two and a half months old.

I've had chicks about half that age (5-1/2 weeks) go through nights with lows in the mid 20's Fahrenheit with no supplemental heat. They did have great ventilation up high and great breeze protection down low where they were.

I cracked it to allow fresh air into the coop, but now I'm wondering if that was a bad idea

It wasn't that bad since it was above freezing. If it had been below freezing blocking the ventilation and trapping the moisture from their breathing, their poop, and evaporation from any open water is a recipe for frostbite.

Unless they are exposed to the elements like a freezing wind and just can't get out of it or it gets really cold (well below zero Fahrenheit), the danger is not that they will freeze to death. The danger is frostbite. They can get frostbite whenever it gets below freezing but if they and the air is dry they can handle temperatures below zero Fahrenheit. If the air is humid or they are wet it doesn't have to be that much below freezing for frostbite can be a risk. Good open ventilation is a good protection from frostbite.

I'll mention ammonia. Wet poop produces ammonia gas, which can be toxic to you or chickens. Ammonia is lighter than air so it will rise and go out of the top of your coop if it can. Most of our coops are not so air tight that ammonia becomes a problem. About any opening above their heads when they are on the roost will keep them safe. If your coop is so air tight that the ammonia cannot escape it can be a problem. I don't know what your coop looks like but I'd imagine even when you had that vent closed the ammonia could still escape. You probably did not endanger your chicks that much by closing the vent. Opening it is better protection in the cold.

Heat can be more dangerous than cold. You really want good ventilation as it heats up.