Coop Readiness - How soon can chicks go out in a coop?

I'm sure I still have a few weeks to go, but my 7 pullets are currently 4 weeks old. They are getting louder, messier and stinkier and the giant Rubbermaid bin seems to be shrinking daily. I know they will be happier to have more space, but I feel like they're still too small to be put outside in the coop. They've just reached the point where they're comfortable at about 75ish degrees, which I can maintain inside my garage with a brooder light, but my brooder is not very big. Is coop readiness determined by age, size, weather? What are the best guidelines?

Mine are about the same age as yours. They will not go out until they are fully feathered, that should be at around 6 to 8 weeks. I'm hoping that will be 6 wks. They might be ok at 5 weeks, but the temp here is still in the 50's at night.
I've been taking them out of their brooder ( in my shop) and putting them in my sick bay (large brooder) outside during the day. They sure like it out there, more things to see then just the sides of the brooder box.
They still lack feathers on their heads, necks and chest. they look a little ragged.....hopefully in another week or two at the most they will go out in the coop with the hens. However, they will be separated from them for their own protection. Then in a couple of more week I'll open the door so they can join the general population. But I will have an opening they can run under into their safe area if it gets too rough.

They can go outside at 4 weeks as long as they have a heat lamp. I'm looking to put mine out soon once I have a coop open. I'll put a heat lamp out there for them and let them have the run of the coop. They won't be allowed in the run for a while though.

We all do it differently. There are a few different things that enter into when they can go outside. It’s not just the overnight lows but how well they have feathered out and acclimated. The facility they are going into plays into it too.

I raise mine in the coop from Day 1. My brooder is fairly large and I only heat on small area of it. The rest cools down to ambient, whatever that is. Sometimes the overnight low has been in the 40’s and daytime highs have only been in the upper 50’s. Many people would be surprised to see how much time a four day old chick spends in the cooler parts of my brooder, only going back to the warm part occasionally. This way, I don’t have to worry about keeping the entire brooder the perfect temperature. They can find their own comfort zone. And they acclimatize to the cooler temperatures. I do have a very good draft guard to keep direct breezes off them. I think the draft guard is important.
I’ve seen broodies take chicks to the roosts at two weeks and all the chicks could not fit under the broody on the roosts. I had a broody wean her chicks at three weeks. But this was in the middle of summer when the night-time lows were in the upper 70’s. In cooler temperatures, they wait a little longer.

I turn the heat off in the brooder overnight anywhere from 3 to 5 weeks, depending on what the night-time lows are. Last fall, with the highs in the 50’s and lows in the 40’s, I waited five weeks, and then moved them into my grow-out coop, which is not heated but does have a real good draft guard. When they were 5-1/2 weeks old, the over-night low was in the mid-20’s and they did fine. But there were 14 of them so they could huddle and provide some warmth to each other, they had been acclimated, and I had a good draft guard.

When can yours go out? I don’t know what your coop looks like, how well they are acclimated, or what your overnight lows are. With your 7, I’d think they can provide quite a bit of heat by huddling. I can’t and won’t tell you what to do in your circumstances. But I can tell you what I do. I never leave mine in a heated brooder past 5 weeks and I have not lost one yet.

My BR's and BA's have been outside in the coop (also in a brooder) since the day I got them (probably 3-4 days old). Temps here are a gorgeous 50 degrees on a lucky day and down in the teens (or lower) at night. They have a heat lamp, but spend most of their time in areas registering between 70 and 80 degrees. On days that the sunshine makes it into the brooder, they AVOID being in direct sunlight and seek the cooler shaded areas of the brooder. Have been there now for about 11 days and seem to be healthy and happy.

As has been stated, it depends on when they are feathered out and the low temps in your coop. Seems most chicks feather out by 8 weeks.

Wow, thanks everyone! They are feathering out nicely, but still have a bit to go on their head/necks. 3 of my 7 hatched 5 days later than the first 4. I'm a first timer and have just finished building my 4' x 4' coop. It's still in my garage...it's going to take 4 big strong men to move it! Pic attached. Once it's outside, I'll keep them confined to the coop for several weeks while I build out my run.

It's about 60 degrees in my garage and it's unseasonably warm this year in Arkansas. I'm thinking about moving them into the coop in the garage for the next few weeks. By the time I get it moved outside they'll probably be 7 weeks and nighttime lows will be 40's. They also tend to move away from the light and seem to be very good at huddling together when the need to, so I think having a larger area to choose their temp will be good for them, and I'll keep the brooder light going in one corner of the coop.

Since you are in Arkansas, you might want to check out htis thread.

https://www.backyardchickens.com/t/37675/arkansas-folks-speak-up

I moved mine into the coop at 3 and 4 weeks old. (I had some a week younger than the others) I live in Texas, though.

I put a chicken tractor into the coop with a heat lamp. They have done really well. When the big girls are out free-ranging I let the babies out into the coop sometimes. I keep the door to the tractor open though, so they can get to the heat lamp if they get too cold. Yours are plenty old enough the spend some time without a heat lamp if you want to introduce them to outside, as long as it's not too cold. Officially moving them into the coop without any protection from the big girls and without a lamp needs to be done at 6-8 weeks old, but you can do it at any age, really, as long as they do have protection and heat.

I need to add, though, I had to move mine out because I had more babies coming to put in the brooder.

I don't have any bigger hens, so they will be protected in the coop. I think I'll put a lamp in there some time this week and see how they do. Thanks!