I think my budgies might be sick

[Caecilius est in horto]

My family was gone for 5 days on a trip and I just got back. All of a sudden, both my budgies are fluffed up and snowball is shivering. By the way, I live in texas and it is certainly not cold in my room. I suspect they might be sick, but I have no idea how to care for that. Any tips? I just want them to be okay

 

[Caecilius est in horto]

I'm considering taking them to an avian vet just to be safe, especially if they are sick and could spread it to my quaker or other budgie