Assisted hatching is usually done on Day 3 embryos but it could be done on blastocysts in the same manner as we biopsy for PGS. I don't know if your embryos are appropriate for that but at Day 5 I am not even sure it is helpful.
It's probably too late in the cycle to do the biopsy.
Arthur L. Wisot, M. D.
Reproductive Partners Medical Group
Redondo Beach, California