How one can get the helm of hiding

This enchantment, transcribed from the Galdrabók, makes a magic sack that turns you invisible

Procedure

 * 1) Pour blood on a chicken's egg
 * 2) Hatch the egg into a chick
 * 3) Kill the chick and burn it’s corpse on an oak wood fire
 * 4) Place the burned chick in a linen sack and wear it on your head