The pattern is designed to use whatever yarn you have on hand, so the finished size will depend on what you use. I used DK mohair/acrylic yarn on 3.25 mm needles, and got chicks which are about 7.5 cm long.

You will need some felt for the beak and feet, but you could also embroider them with yarn if you have no felt.

Pattern is also available in Dutch here (pdf link).