As to sizing quills, I just pick up several of what looks close (from place where a bobcat, housecat, coyote, hawk, or other hungry critter snatched up dinner and left a mess. Throw those in my bag or a pocket. check 'em for size later. I've got a hole in my stock for the current one. When they get a little ratty, I leave it on a trail-back like I found it eh? Found some Meadowlark last fall, very striking colors. Also, were I a bird hunter, I'd save some from my legal harvest and have solid supply of quills.
AS to copper for a pick. Although the Burra Burra mines produced some 15 million tons of copper ore in their heyday, Copper wasn't discovered in TN until 1843, as those lands had be under Cherokee control until 1836. So there might not have been a lot of copper in TN before that time*. That is for those into this region and timelines and all.
But I sure do like the copper. Haven't made a pick of it, yet.
How long were birds used in mines for gas detection? Surely those birds dropped some quills (or died from gases on the job).
*info from Wiki, might not be perfect-any documented corrections welcomed.