Introducing chicks to the flock

[RoyalHillsLLC]

I have four chicks that my kids gave me for my birthday, February 22. We are now debating when we can introduce them to the flock (we only have one large pen). In the meantime, we have been keeping them in a large dog crate.
I tried putting the crate in the pen with the chickens to get them used to each other. After a couple days, yesterday I decided to let them out for a little while and see how they would get along. Mistake......
One of my chicks was bloody with no skin or feathers left on the top of her head when I checked on her a few minutes later. Will the transistion be any easier when they are a little older? Any ideas or suggestions?

 

[MissChessy]

I was told to wait until they are about 16 weeks old, big enough to be the same size as your older flock that way they can defend themselves.

 

[RoyalHillsLLC]

So the others will not stop at just harassing? they will kill them you think?

 

[thisnthatfarm]

Yes, the olde chickens will kill the babies. I was told by a much wiser chicken farmer that until they are the same size not to put them together at all. And even then you may have to separate them somewhat because they will establish the pecking order quickly with young chickens.