It's a little harder introducing smaller groups than big ones. A larger group, even when young just offers more protection within itself. So with only 2 little ones, they might have to work a little harder to fit in, but you'll have to make some arrangements to allow them to be safe.
Most important is offering places for them to hide or escape that the adults can't or won't want to follow. This could be a piece of plywood leaning against a wall, or additional perches they can hop on. Free range time is a great place because they can spend time together but there's plenty of room to run away without getting cornered.
Also try to incorporate the
See but don’t touch method as others have mentioned. A dog crate can work but maybe put it in a corner so the other birds have less access points and the little ones can scoot to the corner without having beaks come in at all sides. Or cover the top with a blanket so it's less scary when the hens land on top. Then set the crate on some bricks or cinderblocks, one at each corner, to raise it up leaving the floor exposed... only the chicks will be able to fit underneath and they can come and go when they feel ready.
I built a picket fence divider with 3.5" spaces. That was their safe place until they decided on their own when they were ready to roost with the big ones. They were 5 weeks old in this picture.
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