No idea what is wrong with this hen...

[King CreekRanch]

If you are seeing lice, then treat her with a Permethrin based poultry dust or spray. Carefully inspect her ears to see if she has any lice in them - it's possible the head movement could be mite/lice in the ears or ear infection which can cause loss of balance.
https://www.backyardchickens.com/t/805728/go-team-tube-feeding
https://www.backyardchickens.com/t/1151513/pesticides-approved-for-poultry

2X