Oh no! I hope she gets better
I have some pictures to share of my chicks.
Big Mama and The Twins...
The Twins
All the babies are now out in the coop!
Getting used to the big ones.
How many weeks are those younger chicks? When the chicks are about 6-8 weeks old, then that's when you can put them in the coop with the older ones.
I agree with flockwater.
6-8 weeks is about right. If you have warm temperatures in the day, you won't need the light. At night you might want to put a light on depending on where you live.