First time chicken owner! I have four RIR pullets about 2-3 weeks old and they are going feral in the brooder. The temps here range from 79F in the morning to 67F at night. Will they survive being moved this week or do I need to wait longer?
I can't run a heat source to the coop.
Basically I agree with Rosemarythyme. My experience is that they can handle a lot more than that temperature-age chart shows. At a young age, less than 4 to 5 weeks, they need a warm spot to go to so they can warm up if they get cold. They need to stay dry (out of the rain) and out of a breeze when it is cooler. Or be able to get out of a breeze if they need to. Mine are very good about managing things like that at a very young age. Mine typically feather out enough by 4 to 5 weeks that they can handle temperatures much colder than that chart shows. I've had chicks under 6 weeks of age go through nights below freezing. Chicks will often amaze you at how well they handle colder temperatures.
I'd keep them on the coop only for the first week or so if not longer. That keeps them out of the weather and gives better predator protection. The big advantage is that it teaches them where home is, where they need to go to sleep at night when you give them access to the run. That doesn't always work, sometimes you need to coop train them by putting them inside when it gets dark but it can help.
Take them out there when you can watch them and see how they react. They will not be too warm in those temperatures but some shade would be good. If they are cold they will hunch up, fluff up, and start giving a distressed peep. If they fluff up and start peeping take them into warmth.
Don't confuse this with them being afraid of change. Often they will love the new space from the start but sometimes they need a few minutes to get used to it. If they are not fluffed up they are not cold.
It is still too early to be 100% sure but that chick you are holding looks like it could be a male. That comb on a chick that young plus general body conformation are suspicious. Cockerels are often bold, brave, and full of personality. They can quickly become your favorites. I hope I'm wrong but you might keep it in mind as a possibility.