Hi, so I have 16 new chickens (about 5 months old), and I've got them to roost in the outdoor run of the chicken coop, but now that it's getting colder they need to roost in the house. I think there is plenty of room in the house, but they won't roost in there, instead they roost in the run. I know they're not scared of them, because both groups free range together all day. So how do you get the younger birds to roost in the coop with the older ones?
Not sure where you are located so I'm not sure what kind of weather you are looking at when you talk about colder. Someone recently thought in the 50's and 60's Fahrenheit was cold to chickens. With their down coat they are just getting comfortable in those temperatures. But that's not you, I just don't know what schedule you are working with.
With my flock it is normal that the younger avoid the older, especially as they are settling in at night. Usually they stay in separate groups during the day to though occasionally they may be able to mingle. Each group is different. It sounds like yours can share outdoor space without a lot of drama. That is a good place to be in this process.
My pullets tend to start sleeping on the main roosts with the adults about the time they start to lay. Yours should be really close if they are not already laying. Until they move to the main roosts they find other places to sleep. As long as it's not in my nests and is some place predator safe I don't care where they sleep. I put in a "juvenile roost", lower than the main roosts, higher than the nests, and horizontally separated from the main roosts by a few feet to give them a safe place to sleep that is not my nests.
Yours are in the habit of sleeping in the run. It probably doesn't have much to do with them being afraid of the others by now, it's just a habit. So you need to break that habit. The way I'd go about it would be to go down there after they have settled in to sleep at night and toss them in the coop. Lock them in there. If it is kind of dark they are usually fairly easy to catch. My typical brooder-raised broods are about 20 chicks. It takes a while to catch them and toss them in the coop but 16 is not overwhelming. You can manage it.
They might all get the message and put themselves to bed in the coop after one night. I had that happen once with about 17 chicks. I have had to put some in every night for three weeks before the last couple got the message. Usually it takes about a week but each group is different.
I don't bother placing them on the roosts when I put them in, mine aren't going to sleep on the main roosts with the adults anyway, mine are usually around 12 weeks old when I do this. They will find a place to sleep. That first night or two that might be on the coop floor. It doesn't hurt them.
I'm down there at daybreak the next morning when I do that to see how they are getting along. It's never been a problem for me but I think it is a prudent safety check.
Good luck on changing their habits.