I have seen 1 or 2 of my friends make them for their strutters.
They went to an archery shop that had "cat whisker" string silencing material on a roll.
They bought several feet of material and cut it into pieces that were 10" long each. Then, the pieces were bound together at one end with some serving string and whip tied just like serving a peep into a bow string.
Then they had one end to hold while the material was stretched taught and cut so the whisker strands would seperate, they ended up with a "beard" about 8" long.
They then poked a small hole in the breast of the stutter in the appropriate spot and pushed the tied end of the beard thru and secured with a small dab of plumbers goop.
Worked like a charm, and it's life-like as all get out.