He looks only like a week old.
He definitely doesn´t look a week old. Lovebirds will have their eyes closed at 1 week old and barely be able to lift their head. They are very small at 1 week old.
And also i am very certainhe cant see. He comes to me only when I call him. He cant see if I am feeding him formulaa. When Itouch spoon on his mouth then he realises.
My lovebirds when they looked like this were still learning my voice. Most were fed by their parents, I fed one at such a young age and she didn´t come when I spoke to her, I had to pick her up. Couple that with your bird having red eyes, their eye sight will not be as good as other chicks with black eyes. Some lovebirds that hatch with red eyes will turn black with age, others will stay, it depends on the mutation your bird has.
Just try to remain patient while they are growing.
I searched on Googlee that how does a 21 old days lovebird look. And the pictures came with with very feathers like a lot of feathers.
This will come down to the breeding conditions as well as clutch size. Some birds will look older, and some younger.
I compared two clutches of my chicks and found that while some were starting to grow feathers, and clear pin feathers were visible on their flights, other chicks in previous clutches were more like your birds and no pin feathers at all at the same age.
Here are some of my chicks at 20 days old (they are grey looking because my birds are *blue), you can see no pins at all growing in the wing. These hatched at Christmas, so this was early January;
Different clutch, a few years later, in February, quite a visible difference, lots of feathers and pin feathers, nice plump healthy looking chicks;
So I wouldn´t worry too much about what they should look like. As long as they are eating and gaining weight daily, everything is going well. Your chick does look quite scrawny, so be sure to monitor weight.