Hard questions about feral hen/runt chick

[Futuregreenefarm]

I don't plan to hatch anymore. I want to downsize. Only want a few laying hens.
Thanks for your time....

 

[Shadrach]

What a lovely looking hen.
I don''t think the behavior you are seeing is abnormal. Whether you can put up with it is another matter.
As far as the hen is concerned she is top hen with a proven track record of producing chicks. Any male should mate with her in preference to any other hen. This is just how it works and the reasons it works should become obvious if you think about feral chicken life. So, the attacking her son and any other hens he tries to mate with is normal and I get a lot of that here. The senior hens have mating rights for want of a better description.
Her behavior with regard to wanting to be on her own is also natural. Feral chickens and their ancestors made/make family groups, not flocks.
A hen will take on a male (your hens attitude towards her son may well change once he is older) to fertilize her eggs and once the chicks are hatched she may well move on to another male. What they all seem to do is drive the offspring out of the home or away from the family unit if that hen stays with that rooster.