molt (US) or Brit moult 
/ˈmoʊlt/ verb
molts; molt·ed; molt·ing /ˈmoʊlt/ verb [no obj] biology : to lose a covering of hair, feathers, etc., and replace it with new growth in the same place
▪ Snakes molt as they grow, shedding the old skin and growing a larger new skin.
▪ Snakes molt as they grow, shedding the old skin and growing a larger new skin.
