That is aggressive, and I too would worry about using that hen to mother again, unless she has been a tried and true faithful for many hatches and this seems to be a very odd out of place occurrence...still not good.
7 weeks is within the "normal" range that they "wean" or fledge, but a few head pecks to say "don't bother me now" is all it takes. If she is drawing blood, that is beyond what should be done. She may for some reason not like this little roo...perhaps he's gotten aggressive with her (????). Is he ill or some deformity? (Sometimes they others just know and it is often the reason for violent hazing). Were they confined in a small area and she could not get away from the little roo?
At any rate you've done what is needed to be done and separated the little guy for now. I would give him a very, very close health check to make sure he is not harboring some disease the others are trying to haze out.
And yes, if this is her first time mothering (or she is a newer mother) I would personally not jump to use her again. She may not be trustworthy.
LofMc
LofMc