how to tell age of scaly lorikeet

by Jen
(NSW Australia)

I have a rescued scaly breasted lorikeet. He appears to be a baby. He has a slightly darker beak than an adult. He has mostly adult looking feathers, but his wing feathers are only half the length of an adults. His tail feathers either haven't grown yet, or have been pulled out except one. The one tail feather thats left is only about 3cm long. He has been examined by a vet (not an avian vet though) and he doesn't have beak and feather disease.

He can't fly, but does try to. He weighs 65 grams and has a prominent breast bone. The vet said he has a Body condition score of 2/5. Any idea roughly how old he might be? I have treated him for worms and lice (he had alot of lice) and have a diet fact sheet from a bird specialist vet.