If the returning chic looks like the others, then mother hen would most likely not differentiate among the chicks there. They are 5 weeks old now and considerably grown. What may happen,, is the sisters of that chick,,, may see her as a newcomer. The returning chic can also act spooked when returning home.

All this can be overcome by "see but no touch method" of introduction of any chickens to a new flock.
WISHING YOU BEST,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,and
