Introducing Chicks to Free-Range Flock

[Aigle]

This may require some backstory. I help care for a flock that used to be a mixed flock, but now only has two six-ish year old Australorp hens. They fully free range, like without a coop or nest boxes, but they do this within an American style horse barn so that they are protected from our Florida rain and sun.
However, since the ladies are getting a bit old, we are looking for some new chicks that I would be raising. Are there any special precautions I should take to raise the chicks (and later integrate) since there is no specific enclosed area the ladies stay in all the time?
Also, are there any breeds y'all would recommend? I want four chicks, and have been thinking buff orpingtons and buckeyes since laying ability is of no issue, we just want breeds that are human friendly and hen friendly for ease of integration with the current ladies, and breeds that can forage on their own. Much thanks!

 

[Chicken lover1980]

so the best thing to do would be to only integrate them after they have grown into pullet size if that's possible, secondly, I heard buckeyes are pretty good at foraging.

 

[rosemarythyme]

Can the chicks be raised in the barn or is it not predator/pest proof enough to do so?

As far as breeds, since you don't care about egg production I'd look for heat tolerant breeds (generally have bigger combs) as they'd be more suitable for your environment.

 

[Aigle]

Can the chicks be raised in the barn or is it not predator/pest proof enough to do so?

As far as breeds, since you don't care about egg production I'd look for heat tolerant breeds (generally have bigger combs) as they'd be more suitable for your environment.

The barn is not really an option, we get a number of snakes through and the cats and dogs who don't think twice about the adult hens may decide that new chicks look delicious

 

[rosemarythyme]

The barn is not really an option, we get a number of snakes through and the cats and dogs who don't think twice about the adult hens may decide that new chicks look delicious

Setting up something that can serve as predator resistant/proof housing and run would probably be your best bet, so the chicks can get used to being outside and being around the other hens, because they're not going to last long without some sort of housing while they're still smaller and vulnerable (and you wouldn't want to keep them inside your house until they're grown!)

Since it sounds like the chickens will need to be on the alert for predators and able to make their own getaway, have you considered breeds like Anconas, Buttercups, Fayoumis? They're flightier so might stand a better chance in a set up like yours and suitable for hotter environments.