A 4 ply 100% cotton rope
It is everything cotton rope shouldn't be - which is why it is being manufactured exclusively for bird toys. It is short fibered and, therefore, pulls apart easily, which will minimize the risk of entanglement. If you pull on the fibers from the ends or shafts, you will get cotton puffs instead of long threads. 1/4 Inch rope is 4 Ply It is 100% natural and unbleached.
Pictured: Left, 1/4 Inch Superior Cotton Rope; Middle 5/16 Inch Superior Cotton Rope; Right: Supreme Cotton Rope 1/4 Inch Price per Foot