Adding new chicks/chickens to a flock! Need some help/advice!

[chickensss]

So, I am interested in incubating some eggs for some new chicks. I currently have 7 chickens, 6 hens and a rooster, but my coop is fairly small, with little grass space because they are free roaming chickens. But, I wanted to add three more chicks to the flock but I'm not sure how or when to. My chickens get territorial when ducks land in my yard, so I don't know if this is even a great idea. So, my main questions are,
-When would it be good to introduce the new chicks/chickens to the existing flock?
-How do I introduce them, anyway?
-Is this even a good idea, considering my coop is small with very little outdoor space?
-How old should they be when I introduce them?(My current chickens are about two years old) Thank you for any input, and any advice would be great! Thanks again

 

[micah wotring]

Here is a very helpful article.

https://www.backyardchickens.com/a/introducing-new-chickens-using-the-see-but-don-t-touch-method

I hope this helps you.

Micah