When a bird moults it is not uncommon for them to be itchy and because of that they may preen and bathe more often. They may also be less active and sometimes a bit grumpy during the moult. You can provide extra protein during this time by giving commercially prepared egg food or you can hard boil an egg and offer some of it to Birb. I hard boil an egg and then grate the white and some of the yolk and mix together and give it to my birds, they all love it, but if you have never offered this to Bird it may take him a while to try a new food.
If Birb has not been to a vet before it would be good to establish a relationship with one and have him checked out to assure that he is just going through a moult and nothing else is going on.