I am worried about my two budgies. I noticed one day that bluey when standing still was slightly shaking. Then a few days lately Tweety was doing it too. Tweety doesn't do it too much, and it only happens when they are sitting still. I think it may be a cold or something? What do you guys think?

They might just be cold or they might be stressed,

i don't think it should be to bad.

How cold is your house?