5-month old BO pullet has trouble lifting head up, pls help!

[Granolamom]

Just found one of my BO pullets with her head on the ground. She can still lift her head, but has a hard time keeping it up. This is her only symptom, and she was happy and active last night. My hens get layer crumble, kitchen treats, BOSS, whey (from the goats' milk), and ACV in their water. They free-range during the day and are locked up in a coop at night. No sign of injury, and nobody else is sick.
I've brought her into the house and am awaiting any ideas from this wonderful, experienced group of chicken lovers.
Thanks!

 

[Granolamom]

Update: We just found her sister, who is still on the roost (it is almost 9:00 am, and they usually leave the coop at daybreak). Bringing her in, as well. Pullet No. 1 is laying in our quaranteen cage, resting, with eyes closed and her head on the floor.

 

[winnieandchicken]

Hello, I just read something like this last night, I forget the which post... search this site... But this sympton is called "dropping wing" and is maybe cuased by "Botulism". She may ate some toxin containing food/mold/bugs... I read that one member said, feed (maybe with syange or baby drop) 1 teaspoon Epson salt per 1oz of water to flush out the taoxin, then feed with vitamin water. I cannot remember all details, you can search 'dropping wing' or 'head down' to get some more information. Winnie