The archers were for the most part without armor, in their pourpoints, with their hose rolled down, with hatchets and axes hanging from their belts, or long swords. Some were completely barefoot, and some wore hunettes (huvettes in Waurin) or cappelines of boiled leather, and some of osier reinforced with iron (sur lesquelz avoit une croisure de fer: covered with pitch or leather in Waurin )Jean Le Fèvre and Jean Waurin were both present at that battle, and both wrote chronicles that described what happened at Agincourt. Their accounts were not independent: they essentially compared notes after the battle and their two versions of what happened were very similar. I have translated Le Fèvre above, with significant variations in Waurin noted.
Hunettes/huvettes and cappelins were head defenses. Huvettes could be made of boiled leather, but also iron, scales and plates, and were sometimes described as small and round. Cappelins seem to have been a sort of helmet favored by infantry and light cavalry. Le Fèvre and Waurin seem to be describing some of the English archers wearing small helmets with lower, less pointed crowns than the bascinet of the contemporary man at arms.
Le Fèvre de Saint-Remy, Jean, and François Morand. 1876. Chronique de Jean Le Fèvre, seigneur de Saint-Rémy, transcrite d'un manuscrit appartenant à la bibliothèque de Boulogne-sur-Mer. Paris: Loones.