Weird neck jerking

[SammyJoyMonte]

My hen of two years just did a dirt bath then her head starting jerking as shown in the video. I was recording her shaking her body post bath so I didn't think much of it, until I noticed she kept doing it, as video taped. What could this be?

 

[Eggcessive]

It looks like she is adjusting her crop which can be normal occasionally. I would feel of the crop early in the morning to make sure that it has emptied overnight. Let us know how it feels then.