What sweet little guy. I agree first thing is to
take him to a certified avian vet asap. I see two things that should be looked at. His beak might be a touch long and that yellow feather on his chest. The yellow feather could be indicative of several issues which should be address immediately. It could be as simple as pellets vs fresh veggies. One other thing, has he been wing flipping and/or toe tapping? look those up on youtube you'll see examples from first signs to severe conditions.
You can fix this. Have faith, go to a CAV, do your homework and follow through. He's counting on you.
things you
might need to do after the vet visit.
-Address why the yellow feather has turned (according to CAV).
-might need medication
-might be diet related
-might just be a mutation.
-Look for anything that might be causing metal or other toxicity.
-Change or upgrade his diet.
-stop seeds
-introduce sprouts
-stop all fortified pellets.
-stop all multicolored pellets
-ideas for his meals -
nutrition
-get a hanging skewer for some of his food.
-Change or upgrade his toys.
-More foraging toys.
-toys that keep his beak busy.
-Introduce training sessions, flight recall sessions and playtime.
-Increase or decrease his sleep time.
-Increase humidity.
-Shower more or less.
-More overall interaction.
I know you might feel discouraged but this can be fixable. best of luck and keep us posted.