Everything Ive read about beardies says they don't make noise. However mine is, and ONLY when Im picking her up to her back in her tank. Despite the 55 gallon accommodations, she prefers to be outside of it.
She is eating with gusto and doesn't seem to be having any other issues. Any insight is appreciated
From what I know many lizards are capable of hissing when they feel threatened, and I'm pretty sure bearded dragons can as well. One time my dragon wasn't feeling well, and when I tried to pick him up he was gaping his mouth at my hand and I'm almost certain I heard him hiss. Considering you say your dragon only does it when you pick them up, I'd say it's just hissing because they may not be completely comfortable with being held.
I don't think she's threatened - I hold her tons without a problem. Its ONLY when its "back to tank" time. But if they do hiss when threatened, its not a huge stretch to express displeasure. My cats whine a lot when they don't get their way, so I think they're being a bad influence on her. She knows she gets her way more than they do HA HA 8)