We raise most of all our Horned frogs from tadpoles here........some are aggressive no matter what.
I have yet to have any vocalize when we are feeding or handling them, but we try to keep handling to a minimum.
We have some that will make clicking or gulping sounds when they know feeding time is upon them......yes, they have our routine down by now.
Right now, we have over 60 tadpoles that are emerging a few at a time each day, they get a 2 to 3 day break from food until the tails are absorbed and the mouths form fully before we even offer food. They are so freaking CUTE!!!
The smallest froglets will get jumpy at first, but a week into being in rotation of feeding schedule, they settle down and get used to the hands & tongs coming their way.
I have noticed that our most aggressive frogs tend to be the females.......our oldest breeding female is named Jello and I should have named her Psycho Serial Biter!!