cochun (s.xiiiin)In a different interpretation, DEAF coche 3 (cochuns) defines the word in this citation as 'woodlouse', linking it to the etymon kos, formed by onomatopoeia and concerned with pigs (cf. cochon de saint Antoine, 'cloporte', FEW kos 2/ii,1255b).
Since in these Anglo-Norman citations a patient is advised to drink a medicinal preparation to kill 'cochuns', such an interpretation seems unlikely.