Moving chicks outside??

[want2know]

So much contradicting information.

I have decided to post my pictures and info and get a consensus.
I have 3 Australorp and 3 Orpington chicks that are 3 weeks old. Have been putting them outside for the last week in a run. The temps here in Texas are in the 80's during the day, in the 60's at night.
I am using a converting homemade wood dog house as a coop. It has a upper and lower level and I have used to house several chicks in transition very successfully in the past. After reading that some people have started much earlier than I ever had, I would very much get them moved sooner than later. My questions are:
When can I move them out to their coop permanently?
What is the lowest night time temperature that they can safely endure if the coop provides good protection from the elements?

 

[nuthatched]

They look fairly feathered in, they can go in the coop

 

[want2know]

Thank you, I thought so. They are starting to get out of the brooder and I haven't used the heat lamp for a while. It's supposed to be 42 next Monday night, but that's a week away.

 

[rosemarythyme]

Thank you, I thought so. They are starting to get out of the brooder and I haven't used the heat lamp for a while. It's supposed to be 42 next Monday night, but that's a week away.

That should be fine, it gives them a full week to get used to temperature changes and they'll be 4 weeks at that point, so 40s should be fine as long as they have climate protected areas to huddle in.

 

[want2know]

One night it got down to 37, and they did fine.