I apologize for not noticing that I forgot to pack textures into the model, so I updated the model to now contain the necessary textures.
I have noticed that there aren't many Opium Bird models on the internet, so I've decided to upload my version of the Opium Bird on the internet. The model has been modelled, textured and rigged. The rig was made using rigify.
I do recommend to change the transparent in your light paths to somewhere around 30-80 bounces. The default bounces make the feathers look black and weird.
The feathers on his body were made using a hair particle system.