1. an animal, especially a bird or crustacean, that moults or sheds its feathers, skin, or shell
Usage: chiefly British spelling; American English typically uses 'molter'

Examples

• The robin is a seasonal moulter that sheds its feathers in late summer.
• Crabs are natural moulters, requiring a new shell as they grow.
• During breeding season, many bird species become active moulters.
• The moulter's old plumage fell away to reveal bright new feathers underneath.