Unlike other sea birds, penguins moult all their feathers at once. They sometimes look sick, although they are not.
During the moult, because plumage is not waterproof and the body is not well insulated, they cannot go to sea to feed, and they may lose 3 to 4 kg in weight.
A guide to assessing whether a moulting bird requires help can be found here. Please contact the Trust on 03 479 0011 if you are unsure.