Hi Dean
That's one of the problems with the penguins, you can quite easily put the size into the penguins but the difficulty is keeping the colour as they should be and keeping them clean with no chest markings on the cock birds. Good luck with them.
I see you are also after crested bengalese - there is a pet shop by me how has some for sale think they are £10ea, i can find the phone number out if you want it
Ben