Should I be worried about little Lullaby? (Updated)

[chixie]

out of my 3 mallard babies... I have one that is half the size of the other two ... it is strong and very active...

 

[Sweetfolly]

Okay - wanted to give a quick update:
Lullaby is growing!

She and Rainstorm are two weeks old now - developmentally, Lullaby is probably where she should have been a week ago, but I'm seeing daily progress, and she's staring to get a leaner, more "gangly" look. There is, however, a problem.

She simply refuses to eat her starter crumbles. I tried making a mush of ground up Purina Duck Grower, which I was planning to switch them to in a few weeks, but she won't touch that either. The only things she'll eat are chopped dandelion greens and live mealworms.

She absolutely loves the wormy little critters - every time she sees me, she starts running in circles and peeping - I feed them by hand, so she attacks my hand looking for worms - if she can't find any, she'll jump onto my hand and start nibbling at my arm

I posted a VERY BRIEF (13 second) video on youtube of the two of them swimming outside the other day for anyone who's interested:

 

[Wifezilla]

I know this may sound weird, but maybe she is allergic to something in the feed????