Taking them outside is great! Except when its super cold and they would need lots of supplement heating.
I always bring grass in from outside starting at 1 1/2 weeks. But make sure to provide grit
For mine i have a mirror, small roosting bars, if i have sticks ill put some in there for them to perch on.
I also have a xylophone that they peck at.
Scatter food in the brooder they will scratch around for it. Mine kick the food out by themselves.