Hen hatched chick...how long to keep separate?

[CackleBabies]

After three failed attempts with several broody hens this summer, one hen finally managed to hatch a single egg today, and the chick is adorable. Dottie is a buff brahma/buff orpington cross (bred by two chickens I started raising three years ago). I raised Dottie and her 3 siblings when they hatched in a broody box, and integrated them at about 2 months, so I don't know much about how mama hen and babies would get along together with my five other hens and one rooster.

Anyway, Dottie's 2 years old, and this is her first time going broody. Three hens went broody at the same time, in 3 of my 4 nest boxes, each with an egg (long story). Over the course of the 21 days, the other two were cracked and eaten, I presume by one of the broodys. When I checked on Dottie this evening after work, Dottie was extremely protective, even when the other broodys came over to investigate, so I assume she's nervous about them. I decided I should move her out to keep them both safe. I set them up in a large dog crate on my back porch with hay, water and chick starter crumbles. They have settled in and look much more relaxed and now have more room (my coop isn't large, and neither is the nest box they were in). So here are my questions:

How long should I keep them separated from the flock and inside the crate? I raised chicks from hatching and put them out at about 2 months, but this dog crate isn't big enough for that length of time. Plus I know she'll want to start getting exercise again, and I assume she'll be able to protect the chick at some point when they're out, but I don't want to do that too soon.

Second, I wanted at least two more chicks, and our local Tractor Supply is selling chicks now, just a couple of days older than Dottie's. I was tempted to buy a couple to sneak under her but I don't want fatal consequences. Does anyone know if I can sneak a few chicks under Dottie so she has the brood she deserves?

I appreciate all the wisdom, knowledge and advice I can get. Thank you.

 

[SueT]

What is Dottie's rank in the pecking order? If she's high up, she can raise the chick in the flock with less concerns than if she is lower rank. She will likely accept other chicks if you get them to her asap, but have a plan B for all the above...
Good luck!

 

[chickengeorgeto]

I am fond of saying that mother hens do all of their babies heavy fighting for them. Mother hens seem to have a special relationship with the rest of the flock. In my experience it is always best to introduce a hen and new chicks to the flock as soon as the hen has them dried off and the peeps are following her around. This way the chicks are socialized to the real nature of being a chicken. Also roosters tend to take the side of the hen and chicks and usually are quick to punish any hen that breaks the peace.

 

[chickens really]

I raise all mine in the flock from either day one or when ever Momma leaves the nest to feed the Chicks. Rank plays no roles because no one messes with a Broody Momma. My Rooster tidbits for his Chicks and protects them from harm. The other Hens never bother with the Chicks. I put down straw and shavings in a corner of my Coop for Momma and Chicks so she has a nest site on the floor. I put feed and water close to the nest and she takes then there without issue. Mine are almost 6 weeks and Momma still sleeps in that nest spot with her Chicks every night...