This question comes up a lot on the chicken forums I occasionally go to to ask questions or look at pictures. It’s one I myself asked. For those of us who brood chicks inside, it’s a bit nerve-wracking to consider putting the babies from the nice warm brooder outside to the cold coop, especially since we have still had the occasional night close to freezing. This is assuming you don’t have electricity in the coop or don’t want to hang a heat light. Now, I am by no means an expert, but here are my own personal thoughts on the matter, picked up from reading mostly on the Backyard Chickens forums.
The short (and not very helpful) answer to when chicks can go outside full time, is it depends. A slightly more useful answer, is that if the chicks are fully feathered, around 6-8 weeks old (depending on outside temps), and off heat inside the house, they are probably fine outside, depending on the temperatures and your coop. Here are my interpretations of “it depends.”
Are they fully feathered?
A chick who still has only baby fuzz or who is in the process of moulting and has bare spots is going to be more vulnerable to the cold than a chick who has all his or her feathers. Once they have all their feathers, it is like they are wearing a warm downy coat. My duvet is down and I can tell you that Kris often finds it too warm even on the coldest nights of winter. Feathers are great insulators! It sounds like chickens are much better able to handle cold than they can handle heat.
I noticed something interesting watching my chicks feather out though. They tend to get their wing feathers first (and some also get their tail feathers pretty quickly). Then the feathers on their heads and neck come in. Lastly seems to be the ones on their backs and bellies. Remember the Silkie I posted a picture of in my last post? She looks nicely feathered in that picture, but in reality, the Silkies are actually still quite bare in places. In the picture above, you can see most of his back and under his wing is still almost completely bare. There is a strip of feathers on the top of his back where the wings don’t cover, but otherwise he is definitely not fully feathered. (Please excuse the pyjamas, and that picture looks awkward but it didn’t seem to bother him at all to be held like that.)
I don’t think this is an accident. Nature is pretty smart, and I’m betting that the reason the wings and head feather out fastest is because they are the most exposed and the wings can act to help keep the rest of them warm. I actually have my Silkies outside full time already (at around six weeks), but if I were basing it solely on their feathering I would have waited a couple more weeks, especially since some people consider Silkies to not be very hardy.
How many chicks do you have?
Putting three not-quite-feathered-out, six-week-old Silkies outside by themselves is a completely different story from putting them out with ten other, fully-feathered chicks. The other chicks in with my Silkies were around seven weeks old and all of them feathered out much faster than the Silkies. (Some of them were fully-feathered long before six weeks.) I read on the forums somewhere that each chick generates the equivalent heat of a 10-watt light bulb. So 13 chicks produce 130 watts worth of heat, that’s a lot of heat. Chicks raised by a broody hen would be outside from the start and would just run back under mom when they need to get warm. I think chicks put outside as a group together will do something similar. For me personally, this was a big factor in putting them outside this early. They were getting crowded in the brooder inside, and I felt that being a bit cold but having access to more room and fresh air would do them more good than being warm but crowded. I was relying on them keeping each other warm.
Six weeks ago, when I first put the Silkies in with the others, the Silkies were a day old and the others were 7-10 days. I was worried about the Silkies getting trampled since they were so tiny compared to the rest. One of the Wyandottes seemed to adopt them and it was really sweet to see the three Silkies snuggling up under her. Now, she still seems to protect them somewhat and I often find them snuggled into her.
How do the temperatures outside compare to the temperatures inside?
If the chicks are still on heat inside and don’t go outside during the day, putting them from an 80 degree room to a 40 degree coop could be a big shock for them. Our older ones didn’t end up being put outside until they were about 9-14 weeks just because it took us that long to get the coop done. They had been going outside almost every day though and were off heat inside (though the room was heated because the babies were also in the same room). I wasn’t overly worried about a big temperature difference because of how old they were, but I put them out in the morning and just never brought them inside again. Some people suggest not putting them in the coop until after it’s dark because they will be sleepy and it won’t freak them out as much, but I felt the temperature difference was still too great here to do that. Putting them out during the day at least it’s getting cooler gradually for them.
With the younger ones, since they were only 6-7 1/2 weeks old, I wanted to prepare them more. They were off heat completely by the time the Silkies were around 3-4 weeks old (which is about the same time frame as the other chicks too). We turned the heat off in the room about a week after that, and the next week we started leaving windows open (making sure to only open windows that wouldn’t cause a draft over the chicks, as a draft can be dangerous). So while it certainly wasn’t getting as cold inside as it would outside, at least it would be a bit more gradual. Our basement isn’t heated and we could have put them down there as another interim step, as it tends to hover around the mid-50’s right now, but I didn’t feel it was necessary. We had also been putting the chicks outside during the day when it wasn’t raining so they could get used to the cooler air. The first night I put the chicks out, it dropped down to almost freezing. The next morning, they were all up and running about, even the Silkies, so it obviously didn’t bother them too much.
Is your coop well-ventilated but draft free?
Ventilation is very important in chicken coops. They produce a lot of moisture when they breathe and also because they poop so much, so it’s good to have lots of high up ventilation where fresh air can get in and the moist air can escape. But drafts are another story. The baby chicks are in a smaller cage inside the coop for now, until I manage to integrate them with the older ones. Air will move from any opening in the coop, to any other opening. You could pretend there is string going from each opening to every other one. If any of those pieces of string cross where the new chicks are, it’s probably too drafty. (We’re talking cooler days/nights here. A “draft” on a hot summer day is actually a cooling breeze and not a bad thing!) I double checked to make sure even the air from the open pop door wouldn’t be a problem, but the pop door is over the height of their cage so I think it’s fine. That’s why ventilation is usually up higher than the chickens roost, so that the air will be circulating up where the warmer, moist air is rather than over the chickens.
So there you have my long answer to the question. Remember though, I’m a chicken newbie too and this is only my experience. Each situation is unique and there are going to be different factors that could make your situation different.