Bullying one hen

[Chickenmomof6]

Hello. So I have 6 chickens (no roosters) that are two years old, raised together. The bottom one on the pecking order has been bullying another hen. As soon as the bully chases her, the others join in. They chase until she is cornered and being pecked at by all. I noticed her comb was cut so I separated her, cleaned her bloody comb until it healed, and sprayed her with a spray I bought on Amazon to deter the bullying-to no avail.
At night I keep her in the coop in a cat cage and during the day she is in a larger pop up enclosed tent. Neither is ideal because she is not on a roosting bar. When I get home from work, I stay with them outside for a few hours. This is totally draining. I have been doing this il for about 3 weeks. She runs from all of them even though the highest one in the pecking order has been staying by her when they are out, but this one has also been joining in when she is cornered. I have tried putting the bully in a separate coop when she is out, but yesterday I noticed that the second lowest one on the pecking order chased her and of course the others followed and tried attacking her before I intervened. This happened a bunch of times. When this happens, she screams and runs towards me.
I would hate to rehome her as she is my baby and I fear she wouldn’t do any better elsewhere. They have lots of toys, treats and space in their run during the day. Im at a loss. Also, she likes to just relax and chill while the others are free ranging and she hasn’t laid an egg yet this year… Her bum looks all yucky to the point where I needed to use a scissor to remove some dried, caked on poop.
I give them vitamin water, a separate container of oyster shells, I put garlic and oregano in their food and I use neem oil on the roosting bar to help with parasites and mites… What am I doing wrong??? Please I need help with the bullying and her well-being…

 

[aart]

Also, she likes to just relax and chill while the others are free ranging and she hasn’t laid an egg yet this year… Her bum looks all yucky to the point where I needed to use a scissor to remove some dried, caked on poop.

Could be she's sick and the others are drumming her out of the flock.
Sometimes a bird just doesn't fit in and needs to be removed.

 

[Chickenmomof6]

Thanks for the response…Yesterday and today I jailed the two main bullies in a big outdoor run. It seems that 3 other hens leave her alone where they’re free ranging. They may go near her and she jumps up out of fear, but they don’t attack for the most part.
I would be afraid to rehome her as she is so timid and definitely would not do well elsewhere.
You’ve mentioned it and I’ve also read about the hens possibly “weeding out” the sick, but how to I go about finding out what may be wrong with her? I’m assuming bringing her to a specialized vet, but is there another way that u may recommend?