This looks like a baby about 3 weeks old. Are you handfeeding him? Feed him with a spoon not a syringe. Its too easy to accidentally put too much food in his mouth using a syringe and the baby could choke or inhale food and die. It happens a lot when people buy unweaned baby birds, something I wish breeders would not do.
I don't think he's plucked. Babies don't pluck. His feathers are just coming in. Keep him warm until he's fully feathered In a week or two.
What DonnaBudgie said. The baby looks quite young, as their feathers are starting to come in. And definitely spoon feed if you're hand feeding the baby. I lost two babies to syringe feeding when I was hand feeding cockatiels about 20 years ago. It was a horrible, horrible feeling.