it seems to have a splayed leg
Some info to have a read of;
What is it? Spraddle leg, also known as splayed leg(s), is a condition where the legs of a chick are sticking outwards and the chick is not able to support it´s own body weight. A chicks legs should sit vertically under the body and not at an angle. What causes it? Insufficient bedding in the...
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Be sure to act quickly. The quicker you seek help, the best chance of success you have. If the bird is feathered, I would be making plans to get him to the vet asap.
Is it safe to be removing it from the nest and handling it?
Sure if he´s not too frightened. You can even offer some little millet seeds to the youngster from your hand to show him you mean no harm.
Millet spray is a really good choice of food, most little birds LOVE it, and you can cut it longer or shorter to match how comfortable the bird is with you. Start by offering a longer piece, and you can make it shorter as they get comfortable around you.
I did put the baby back in the nest after a while because all it did for a few hours was sit in the corner
I wonder how able he is to move around. A young bird should be quite active and adventurous. At first they might sit still observing, but most ill start to explore after a while.
Monitor closely to be sure the parents still feed it, but the birds should be coming out of the box now to wean to start eating things on their own. Did you put food on the ground level for the little one?
As a side note, if you post a clear picture of your birds cere in natural light, some members of the board might be able to sex him/her for you.