Treats for ducklings

[Duckmomofnow2]

I was wondering if there is any specific brand of mealworms to give baby ducklings as a treat? Also how can I tell how old they are? I got them From Tractor Supply on April 22nd. The picture on the left is when I got them and the picture on the right is them today.

 

[Miss Lydia]

I buy dried mealworms from eBay 44lbs at a time and so far all I have bought different brands depending on price mine have loved even as tiny ducklings.
And if you want them to have a really good time buy a treat ball and put the mealworms in it and watch them have a blast rolling the ball around scarfing up the dried worms as they fall out.
https://www.tractorsupply.com/tsc/product/manna-pro-chicken-toy