Introducing 3-ish month old chicken to younger flock

[mybelovedchickens]

We had 6 chickens when the neighbors dog attacked and only one female survived so we just got 6 more baby chicks and I'm not sure how to introduce them. I've read people add younger chicks to a flock at night but this is the opposite problem, I'll be introducing an older chicken to a flock of much younger ones.

Should I add the older lady to the brooder until the younger are old enough to stay in the hen house or should I leave the older one outside alone?
The older one is about 3 months old, she's not laying yet and she is a gold-laced Wyanndotte, the new baby chicks are Australorps maybe a few days old.

 

[aart]

Best case scenario would be to brood new chicks in a section of coop,
where older pullet can see but not touch them,
then integrate them around 3-4 weeks.
https://www.backyardchickens.com/articles/integrating-new-birds-at-4-weeks-old.72603/

Pics of your coop and run would help here.
Hopefully raccoon issue has been repaired?

Oh, and..... Welcome to BYC! @mybelovedchickens
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[mybelovedchickens]

Thanks! I'll have to go ahead and update my account
We didn't have a raccoon issue, our chickens were free ranging when the neighbor let her dog out and didn't leash it (even though its required in our area). Right now I've been taking the littles out during the day and putting them in the run connected to the coop in a smaller portable 'run' which is actually just a reinforced squirrel guard for out raised garden bed. So far its been working the older hen occasionally pecks at the younger ones faces but she is also just sitting outside the smaller run instead of hiding in the coop all day like she was doing before.