Time to put in 3 sided outside coop?

I would make sure that they have a place to pile up to sleep, like in the doghouse that you mentioned.

at 10 weeks they should be fine... but if they have been used to a 70 degree house, you might need to add a heat lamp.


It might be easier, and have less risk of burning everything down.... if you let them stay in that shelter every day, and let them sleep in the dog crate in the house every night.. for about a week, to help them get used to the temperature a bit (and it might get warmer in a week)

 

once they're fully feathered, they're totally equipped to handle the weather, just like the birds in the trees

 

Very good advice. While I am new to chickens, I not new to birds. I have 20 or so exotic finches. Though a bird might be adequatley "dressed" for low temps, if they've been used to being inside, they will need time to acclimate to the lower temps. Think of it this way: If you were dressed for 30* weather, but were inside all day, you'd be uncomfortable when going outside. It might not kill you, but you would be uncomfortable.

Owners of exotic finches know not to put their birds out until night time temps are high enough that you wouldn't be uncomfortable with. That may not be an option with chickens. So the above suggested ways to acclimate them are, IMO, excellent.

 

My 3’ x 6’ brooder is in the coop. I heat one end and keep it toasty but let the far end cool off as it will. On occasion I’ve seen ice in the cool end when the temperatures get in the single digits but the chicks stayed on the toasty end until it warmed up some.

I’ve had five week old chicks go through nights in the mid 40’s in an unheated grow-out coop. I’ve had chicks go through nights in the mid 20’s before they were six weeks old in that same grow-out coop. Once they are feathered out they can handle cold very well, but there are a few considerations.

In my brooder they are acclimated. They spend a lot of time in the cooler end, just going back to the heat when they need to warm up. That also seems to help them feather out faster.

My grow-out coop has good ventilation up high but has really good draft protection down where they are. The ventilation allows an exchange of bad air for good. That bad air includes ammonia from their poop and moisture from their poop and breath. Ammonia can damage their respiratory systems and just like you and me, damp air feels colder than dry air. Excess moisture in the coop is a strong contributor to frostbite. Draft protection does not mean you close them up tight. It means you stop breezes from hitting them directly. Openings up high accomplish this.

There were about 20 of these chicks. There were plenty to keep each other warm if they needed to, they just sleep in a crowd.

People use open air coops way up north. They can work quite well, but that does not mean you just replace one or more walls with wire. You create a coop with a dead air space inside for the chickens looking at air flow. I’ve seen adult chickens sleep in trees in zero Fahrenheit weather, so chickens can handle some really cold temperatures. But these trees were in a protected valley and the chickens had the freedom to move to get out of a wind. They don’t always have that freedom in our coops.

I recently saw something trending online where a bald eagle was on her nest covered with snow. She was protecting her eggs from the cold and snow. She had some protection from wind by the sides of her nest and she could turn around to face into a wind so the lay of her feathers deflected the wind, but she was fairly exposed. Chickens are closer in this regard to eagles than tropical birds.

At ten weeks old your pullets should have no trouble outside with those temperatures, but I’d block off the open side with plastic or something to block the wind for a week or two. And put some bedding in that dog house that they can snuggle down into if they wish.

My brooder raised chicks normally go to the roots around 10 to 12 weeks old. I have had some start roosting overnight at five weeks and some that took a lot longer than 12 weeks, but most start around 10 to 12 weeks. I don’t know how you are set up for roosts but if they have that option don’t be shocked to see them spend the night on the roosts instead of on the floor of that dog house.

When to move them out is a dilemma. We are all unique in the way we manage them and in our facilities. With just a little help they can manage quite well, but they do need a little help.

Good luck!