Okay, think first about the food you are giving them. If it's not soft enough, a duckling can think it's choking on a chunk of food.
So, don't hold her. That's stressful for ducks. Their parents don't hold them, only predators hold a duckling. (As she grows up, you can get her accustomed to being held as a good experience. Right now is not the time to teach her that.)
if she's making noise she is breathing, so she will be able to get over the feeling of food stuck, in a little while. Just give her some quiet time, and make sure water is available to her.
i just had this happen, my nephew poured in some Mazuri duckling feed without soaking it in water first. I don't know why I videoed it--it must have been for you! (It's not a great video, sorry.)