Yes I definitely notice this. The roosters are the exception, but the hens of the same breed tend to be closer than with hens of a different breed.
It also has to do with who they were raised with as well. If you have a barred rock and a wyandotte and add more barred rocks to the flock, the barred rock will not abandon the wyandotte just because there are other birds that look like her.
It also has to do with who they were raised with as well. If you have a barred rock and a wyandotte and add more barred rocks to the flock, the barred rock will not abandon the wyandotte just because there are other birds that look like her.