So geese like to steal things and get aggressive when provoked - I made the mistake of spam throwing eggs, which of course then hit a baby goose for 0 damage, provoking all others in the cage.

Long story short, I died, dropped all my items and didn't immediately know how to get them back (seems dropping seeds on the ground is the go-to way), so I ended up killing them.

Adult geese do drop what they are holding but I learned the hard way that baby geese don't and lost some important items due to that.

Thanks for reporting! This is due to the fact that baby entites by default don't drop their loot.
I disabled goslings from picking up items now. Since they also don't attack you I think this is the most sensible solution.
Will be fixed in the next release of the mod.

Makes sense, although I do think baby foxes do drop the item they are holding, this is just as good of a solution.
Thanks for the quick reply!