I just buy a bag or two of frozen peas and thaw a cup full in warm water for a little while, don't get canned ones they have too much salt. They definitely work mine go nuts over peas and dandelions leaves so far there is an awesome sticky called the ultimate list of treats and supplements for ducks it has so many treats you wouldn't even think of and ones to avoid and also what ages certain ones can be given. When mines were that small I would crush the pea up with my fingers before I gave it to them oh and also that is so sweet she is attached to your silkies, post some pictures when you get a chance!
Here are a few pictures