Also think about more local options and forums that have buy and sell theads. E.g. in the Netherlands we have the tweakers forum, which would be an ideal place for this.

If you are really really curious, you can find a phlebotomist that is game and use your own blood. This is the most ethical way to get some cooking blood and it can be done. (For proof see article)

https://www.vice.com/en/article/i-made-meringues-out-of-my-own-blood-and-ate-them/