Is it warm enough for my chicks to stay outside now?

baby chicks need to be kept inside in a warm light for a few weeks, im not sure if 6 weeks is old enough to be outside, but 40 sounds pretty low for a baby chick

It depends on how cold it is inside the barn, but if they have all their feathers then you could put them outside during the day and bring them back in at night.

Most chicks go out between 5 to 8 weeks depending on breed and temperature. I personally would go ahead and put them out. They will need a hutch to get into out of the wind and rain. If it gets too cold, then just bring them in for the night. Here are a few sites that I enjoy......

Katy's site. She has a ton of fun

http://home.centurytel.net/thecitychicken/pictoria...

A portable pen (very redneck, haha)

http://www.henhutch.com/

This one is very nice indeed

http://world.std.com/~kcl/chickencoop.html

Great site

http://www.backyardchickens.com/coopdesigns.html

Hope this helped. Have fun with your chickens!