Blood found on my ducklings underbelly

[Brailey]

Does anyone know what this can be ?
This little guy is 5 days old

Watched him poop after I noticed it so he’s relieving himself fine

 

[NatJ]

Does anyone know what this can be ?

It looks like the umbilical cord.
A scab there is normal. Bleeding from that area can be concerning.

Watched him poop after I noticed it so he’s relieving himself fine

That was a good thing to check

 

[Miss Lydia]

Put some antibiotic ointment on that and keep the duckling on clean bedding preferably towels until that is closed up completely. You don't want that to get nasty bacteria in it and cause infection.