One of my babies seems to be minus one tail

During the crate clean and best check (while Poppy was off nomming treats) I noticed one of my kits seems to be missing their tail. I can't be sure they weren't born like this but it seems much shorter than the others and has a sort of liquid tinge to it - not blood but like a clear fluid.

Eyes are open today but could one of the others bitten it off? Do they have teeth at this age.

I can try and get a pic if it would help. If it hd an injury do I ends to do anything or will it heal?

Edit: definitely got a bit missing. Took some pics:

Poppy may have bitten it accidentally. I've heard of young/inexperienced mums overgrooming before. It does look like it has been bleeding. I'd give the vet a bell and ask whether you need to put any anti-septic stuff on it or not. They will have an out of hours phone service.

eta - just wanted to add to keep stress to a minimum for mum, I'm sure it is probably just because she is very young, but stress has been linked with overgrooming/injuring kits.