Why do they store plump spawns on the office chairs

[Red Heifer]

https://steamcommunity.com/sharedfiles/filedetails/?id=3126426682

[Fel]

The likely answer is that you do not have a proper dining room with tables anc chairs, so some dwarves ended up eating there, and what they ate were plump helmet.
Add to this the fact you don't have a stockpile for seeds (preferably only seeds and remove the use of barrels for it), not enough bags for them and/or not enough dwarves not already working all around the clock to handle them.

[AlP]

Why do you have chairs in empty rooms?

[Fel]

I would assume they are offices, but it makes the big room in front a bit weird in that case.

[Red Heifer]

Originally posted by Fel:

I would assume they are offices, but it makes the big room in front a bit weird in that case.

That makes sense. I had a dining room near the kitchen but they kept going there to eat. Yeah the big room, is just an area to build offices onto from the z level. I copied it from the room above. It's a little wonky lol.

[Fel]

When dwarves are hungry, they grab the closest food (direct distance through floors and walls, not path distance) and then go to the closest place to eat.
If possible they prefer to go to a place with a table+chair combo, if you have enough of those (1 table per chair by the way) in your public dining room (and preferably none in other public places, they don't use private ones of others) they should eat there most of the time.

Those that own private dining rooms will prefer to eat there, and your offices are probably not given to anyone so they count as "public".
The lack of tables should discourage them but if such a number of seeds are found there you probably have issues with your dining room.