Introducing chicks and some other chick questions. Help please :)

[saraiquimby1]

Can I put new chicks in with my current chicks? I bought 12 from a feed store( so suppose they are 3-4 days old) on March 11. So I am assuming my chicks are about 4 weeks old.. I got a few more from a farm store, can I put them all together?
I'm planning on keeping them separate for a week or so so the little ones get their feet and make sure they are healthy. But after that can they all be together?
These are my chicks now





My next question is is it normal for chicks to chest bump each other a lot? And they jump at each other and like "kangaroo kick" each other. (can you tell this is the first time I've had chickens? ) I'm 99% sure the Barred Rock is going to be a rooster (Judging by his attitude and what others have said on here) and he does it most. But the others chest bump a lot. Is that an indication that they are probably roosters too? Not all of them participate.
Any insight is appreciated.
Thanks in advance!!

 

[Egghead_Jr]

You'll need a separate food and water as the larger birds will crowd out the smaller. I've not put birds together when one group is so young. With the same age difference of 3 weeks I've put birds together when the younger birds were 3 weeks of age. It still required separate water and feed. It took them another month to fully integrate.

Either sex will chest bump.

 

[newmarch2014]

It sounds like you are planning it well. Keeping them totally separated and washing your hands between care to make sure no new stuff is passed along till you make sure they are healthy is good. Once you are sure and ready to put them together you can put up a screen barrier that will give them a chance to safely get used to each other that can be taken down after a few days with water and food for both sides.