When should chicks be introduced to the flock?

[Immensely_Confused]

I currently have two hens who are wonderfully co-parenting a pair of chicks, and they've been kept in the barn, away from other chickens, since around the time the chicks hatched. The chicks are now three weeks old. We did that because 1) the other chickens were stressing one of the hens out, 2) we have some cats who might look at young chicks as food, 3) we have a hawk problem, and 4) we also had several young cockerels at the time who had behaved aggressively towards smaller chickens.
Now, the weather is getting colder here, and the chicks are quickly becoming fully-feathered despite their age. The cockerels have been dealt with, and they're getting to be the size where our cats stop looking at them as food.
Should we do introduce them when they're larger, even if there's a chance of the hens weaning them off before that happens? Should we do it when they're younger because the hens will be looking after them, even if there's a higher chance of predation or them being bullied by the flock? [The chicks are confident to a fault, and fly everywhere; the poor hens just try their best to keep them out of trouble.]
When should we introduce the chicks?

 

[BDutch]

Do you free range your chickens? Or have an uncovered open run? How much space for how many chickens? Are there hiding places?

If the chicks are protected against predators, and you have enough space for them all, there is no need to keep the mothers and chicks apart from the rest. The mamma’s will defend the chicks against the other flock members.
Give your flock chick feed in several feed stations to avoid problems. (grit and oyster shell on the side).

Free ranging with a small risk of predators and plenty hiding places is a possibility too.

 

[Yardmom]

I would integrate sooner rather than later. The older the chicks the more older birds feel the need to show their dominance. Be aware that the mamas may scuffle in their instincts to protect the chicks, but also because they have been out of the flock for a bit.

 

[Immensely_Confused]

I would integrate sooner rather than later. The older the chicks the more older birds feel the need to show their dominance. Be aware that the mamas may scuffle in their instincts to protect the chicks, but also because they have been out of the flock for a bit.

Thank you.

Do you free range your chickens? Or have an uncovered open run? How much space for how many chickens? Are there hiding places?

If the chicks are protected against predators, and you have enough space for them all, there is no need to keep the mothers and chicks apart from the rest. The mamma’s will defend the chicks against the other flock members.
Give your flock chick feed in several feed stations to avoid problems. (grit and oyster shell on the side).

Free ranging with a small risk of predators and plenty hiding places is a possibility too.

We free-range, but also have a coop with a somewhat-covered run in case of some emergency. They have plenty of hiding spaces and many forested acres to use, but birds of prey are a big issue. Thanks for your input