Don't know if you need the answer still, but you'll have to turn the generator on for the last two. Dont want to spoil directly, but the crow is near the générator, and the snake is on the right side when you enter the lab from the outside :p
The other two statues (bird and snake) can only be found after powering on the generator, use a key card on the semi-hidden pannel by the generator and it will turn on.
