Screaming while biting his leg

[cringybird]

I have a 6 month old Caique. Ever since I got him he would suddenly start screaming and bite one of his legs (like thigh part) for a while before going back to being ok. He does it at least once a day and its on the same leg every time. Up until now I thought maybe it was normal behavior since he is still learning how to preen himself and play around but recently i noticed that a tiny part of the leg (where he bites) doesnt have many feathers anymore.
He gets his daily out of cage time and his diet is good its mostly veggies with pellets. Everything else is great, he play all the time, will fly around and just destroy his toys. He doesnt have any other parts with no feathers either. I've taken him to the vet and he said everything was healthy. I'm not sure whether I should insist on checking him over of it is truly normal for him to do this.
He's never bitten me and if he does its softly and just around my finger to "groom" me.

 

[April]

@Irishj9 @Laurie Have you experienced this?

 

[Charlietoo]

Mine does that as a frustrated behavior

 

[budgie 2]

Does he have one of those metal rings with numbers around his leg?

 

[Irishj9]

Mine never do this. I suspect theres aphysical problem there which is bothering him

 

[sunnysmom]

Maybe take a video of him doing it to show your vet?

 

[Shezbug]

I think a vet visit for some investigation sounds like the best option. Missing feathers and screaming while biting a leg does not sound anywhere near normal to me.

 

[parrotcafe]

I would have your avian vet examine him. He may be experiencing nerve pain.

 

[cringybird]

Thank you everyone, I'll post a video of when he has those moments for reference when im home and let you know what the vet says for others in the future. I'm going to get a second opinion.