tecnical problems in my photos

First:

• Your direct flash introduces hard shadows and overexposed areas.
  
• The tail is cropped, the picture would be more usable if the entire bird is in frame.
• Your box has light leaks that distract from the subject.
• The carton box may be effective for what you want to do, but it's probably not great as a picture background, neither for friends of nature nor for friends of cage birds.
• Your in-camera processing did "denoise" correctly focussed feather detail. It took the detail for noise. Other parts of the birds body are over sharpened.
• The bird’s eye is not sharp. That is absolutely necessary for portrait shoots.
• Out of focus area is washed out and contains artefacts from bad denoising algorithms.

Second: Same camera same processing problems:

• The denoising sometimes takes legit structures for noise, and "washes" it out...
  
• Despite being denoised,  you still have a lot of noise in the picture.

Third:

By now you know it: wrong composition. You need to get the whole bird's feather in the picture. And you need to take care of the artefacts:

There are other defects that all by itself lead to a refusal.

Fourth: Oversaturated, grainy and bad overall composition. In addition, you should photoshop disturbing elements out of the view:

No need to start with this picture, it is anyhow doomed.

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I think there are probably many things you still have to learn about the expectations in commercial photography. I'm just looking at shot planning/composition here. To pick just one point in each picture:

- the bird's tail is cropped

- the tower is leaning

- the feather shot is marred by distracting white posts

- the building has power cables and another object in the top corner