Poultry cell has b vitamins and selenium and can be given directly, added to water, and I’ve added it to the food before as a mash( because they always spilled the water so I felt like I was wasting it)
In a pinch sugar water can perk them up quickly too, but that won’t fix the underlying problem.
For awhile I could actually tell which crow was which from each of my roos. They are different and I believe the hens know who’s talking when they crow!
It varies probably, I used to have a pair of mystic onyx and their eggs were about the same shade as my barred rocks/buff orpingtons maybe a bit lighter.
I think a similar thing happened to my chicken where her eggs stayed too damp and because of that I think they didn’t lose the air they were supposed to and they “drown” in the shell. Them being damp for awhile also could have let an infection in as the other poster mentioned.
She does look scalped which isn’t uncommon from older hens to young ones especially if they don’t have a mother to protect them. Keep an eye out for any aggression towards other birds.
Monitor it. Don’t try to rinse anything until maybe tomorrow so it doesn’t start back up again. He should be fine. If you really want you can use vetricin or saline but I don’t think it’s needed.
Never dealt with this. Warm blankets or water bottles can help in people, you want to be sure not to heat her too quickly because they can go into shock.