why would you narrow down so specifically if you just want a pet?
I've seen stuff about Blue mutations before and have heard (nothing confirmed) that they often have a slew of health problems due to inferior genetic traits brought out from just trying to get the coloring. I'd just look for a bird that likes you and you like, far easier that way. Also you'd pay through the nose for a blue mutation, like easily 3x the cost of a normal bird. Also looking for at both Europe and the USA if you're getting from out of your country/ out of region say for example you're in Europe and buy from USA or vice-versa there is a long expensive process in getting them sent to you involving numerous documents both legal and from the vets along with a quarantine in many places and multiple health checks by vets which at a young age could cause some severe trauma to the bird