They should be fine at seven weeks if they have plenty of food and water.

What I know about the cold is that if they are all huddled together it is too cold. Usually when I think it is too cold and expect them to be huddled they aren't. They are walking around doing what chickens do. Eating. Firefly did you let them spend the night outside? How did it go?
My Delaware peeps are about 3 weeks old and I am looking forward to being able to let them out with the adult chickens for more than a visit. The Mom wants to pick a fight with any hen that looks at her or the chicks. She doesn't mess with the roosters.
Suellen

Thanks for the advice, you two! I did let them spend the night out-- actually the last few and they are doing fine. They are funny though-- when I first put them in for the night, they like to find a spot in the shavings on the floor and huddle together to sleep (it has been in the 60s-70s when they go in) but when I go in the morning they are all spread out on the roost snoozing (first thing in the morning its typcially low 50's in there)-- strange!

And yes, their food and water are in there too so they are all set. Thanks again!