In the meantime, You can hold right click down and move your mouse down through a row of ducks to funnel them all the selected bread. Making it much easier than 1 at a time.
i did have that figured out but that is arguably still doing it 1 at a time, but it is indeed a QoL.
However, since the export is Json, i've just replace "attached_bread":"" with "attached_bread":"Wheat" in VSCode and reimport, kinda saved scrolling over around 2k ducks this way already , maybe later I'll use Json editor online and figure out how to set different attached_bread per duck tier 🤣