What age can chicks go out!

Hi,sorry to seem silly but my chicks which have started to hatch today,what age are they ok to go out into the big wild world!? Or do I just let Mum do all the work?

they were younger than that Grannie - about 2 weeks old, but I had to make sure any crows and rooks leaving their nests nearby had passed over so it was usually about 10am (this gave them chance to fill up on chick crumb) and then had them back in their coup by 4pm. I would only do this with chicks that had a broody mum and not incubator chicks.

If their incy chicks i put them out between 5 and 7 weeks depending on the weather and if they are fully feathered :)i put them on the patio first in a covered run then slowly introduce them to grass then when they are about 15 weeks they go down to my plot on the allotment and get to play with the big girls