Two of my hens keep shaking their heads, what is this a sign of?

[RooandherRooster]

Hey everyone
One of my hens just got over from being egg bound, she had everything she needed but we figure its because she is getting old. The other one was egg bound about a month ago too. They are both about 3 going on 4, and Red Sex-Links. Both were fine until today. I was keeping an extra close eye on them as one is pale and the other is just getting her color back and getting her comb upright again. The pale one might be starting to get ready to lay an egg. Every time she lays an egg, she slows down now, almost egg bound but passes it on her own but doesn't look good.
Well today I noticed she was much paler, and laying around way more. But before I went in to check her, I saw that she kept shaking her head. Fine, a shake. Fine, a shake.
I remember one of my other RSL did that one night but her crop was way over to her right side, and I went in to look it up and I can't remember what my diagnosis was. They may be more stressed out though, because we added in chickens to their flock 2 days ago.
Anyways, then I saw the other doing it lighter, just a little shake though. Why are they doing that?
Any help would be very appreciated, thank you!

 

[Wyorp Rock]

Have you looked them over really well for lice and mites? Look in the ears too for any debris or infection.

Check their crops to make sure they are empty in the morning.

For hens that seem a bit week or are recovering from a stressful event like egg binding, I give them a direct dose of poultry vitamins for a few days. I like Poultry Cell - give 1cc per 3 pounds of weight.

 

[RooandherRooster]

Have you looked them over really well for lice and mites? Look in the ears too for any debris or infection.

How do I do that exactly, look in the ears?

Check their crops to make sure they are empty in the morning.

For hens that seem a bit week or are recovering from a stressful event like egg binding, I give them a direct dose of poultry vitamins for a few days. I like Poultry Cell - give 1cc per 3 pounds of weight.

Okay I will. I am also giving them Oregano and Cinnamon Leaf essential oils in their water, and herbs too.

 

[Wyorp Rock]

Okay I will. I am also giving them Oregano and Cinnamon Leaf essential oils in their water, and herbs too.

Are they drinking the water o.k.? I would also provide them with plain water too just in case they aren't drinking the water with the essential oils.