Blood for Wyverns. Is it actually possible to do?

Vasik seems to have experimented with this, and Gerter might have as well. The point is this: You can give blood to any creature in the game, except for wyverns. So, you could try changing the wyverns' ID to another creature that doesn't have too many game mechanics tied to it. For example, hydras. Swap everything around: give the wyverns the hydras' ID, and the hydras the wyverns' ID, change their castles, and so on. Then, give the wyverns blood based on the hydras' ID. This might work.