Normally Kookie is always interested in new things if they are small, apple size or less, but whenever they get bigger, he is either curious or scared...I took the advice of some members here and I introduced the boa slowly, first I put it at the far end of the room, then caressed it and played with it several times saying the word nice and good boy...everyday I brought it a bit closer and finally I put it on the floor bellow his cage and tied some almonds to it. In 2 hours the almonds have vanished and I knew that Kookie was not scared anymore. He kept off it for few days, and climbed on it only if there were some almonds on....now he is on it almost all the time hanging and swinging like a monkey...
The best way is a slow introduction, though it doesn't work with everything. Despite all the things I tried with the harness, Kookie still would not accept it on him, he gets terrified....
You have to keep trying and introduce slowly. The more your grey gets introduced to new stuff the less he is scared from other stuff.
Have fun & good luck