Pretty much - finally, someone gets it!
OK, so as part of last night's session, I got the chance to talk to both the fletcher as well as the baron's chief administrator and sage (who is knowledgeable about maps and local flora/fauna).
Ideas that did not work:
Sympathy – I looked it up and that is a 9th level druid spell, so I don't have it. Pretty sure the wizard doesn't have it either although it would only be 8th level for her. Regardless, the spell description says it only works on intelligent creatures, so no dice all around.
Sending the women and children out to find feathers – we have already encountered orcs from the bandit party accosting a farmer and his family in an outlying area, so it would not be safe for them to go out unattended.
Prestidigitation – it was a DM call to see if it could regrow feathers, and he said no.
Did not discuss these (yet):
Wild shape – ouch.
Teleporting to other towns to buy materials – don't think I will need to, but that may still be an option.
Control winds – will probably save this for combat.
What should work:
He said that crows would be fine, as would geese and other fowl. The sage has maps which indicate where specific types of birds can be found in the local area, and spamming
charm animal and
dominate animal for a day or two will probably get me all the feathers I need. I forgot to ask the fletcher for some cages or something, but all I would have to do would be to capture the animals and surrender them and then beg the gods of nature to forgive me.
Speak with animals may also be necessary, and
baleful polymorph may still have promise.
Probably next session, after I finish running my other remaining errand, I can focus on gathering the arrow parts so that the townsfolk can construct them.
Also learned some other important info. Apparently I badly misremembered the size of the raider camp – they are actually a much smaller army than I original presented on the first page of this thread.

Their numbers are actually less than 2000 total! The first wave, the tribute gatherers, should consist of about 200 orcs and several giants, and will likely be led by a few humans. So, nowhere near the overwhelming odds I originally thought they were.
