Looks kind of like a turkey egg. LOL
Your Welsummer doesn't look like she's ready. (but my Welsummer does have lots of speckles - but on a darker egg)
Your Barnevelder or Marans will likely lay dark speckled eggs. Perhaps the hen just had an odd egg since she's starting out.
I have a couple orpingtons that lay speckled eggs. Usually from the same hen.
So I guess the top options are one of the Wyandottes or my Marans had an off day? She did not lay today (unless that was hers) but all 4 of hers so far have been much darker than this one. It just might kill me waiting for another one to try and catch someone in the box. I knew for sure with the other 2 who was laying because they made it super obvious. This little chicken is making me do the work.My guess is one of the wyandottes
My GLW sometimes gives an egg like that.