Hypothetically

[wilkinsfarm2020]

How would crossing a welbar hen to an olive Egger rooster go?

 

[NatJ]

How would crossing a welbar hen to an olive Egger rooster go?

Probably some daughters will lay olive eggs, but some daughters may lay brown eggs.

Olive Eggers can have so many different colors and physical traits that I can't predict what the chicks will look like. Posting a picture of the rooster would help with that.

 

[wilkinsfarm2020]

There's a few! He's still a baby

 

[NatJ]

There's a few! He's still a baby

With that coloring, I expect he will produce lots of black chicks.
I think he might be a dark blue, in which case half of his chicks will inherit the blue gene (turns all black on the chicken into blue.)

There is a chance that half of his chicks will be black or blue, and the other half some other color. I can't tell if he is carrying the right recessive genes to make that happen, or if he will produce only black chicks and blue chicks.

Since he has feathered feet, probably some or all of his chicks will too.

The same goes for crest on the head, muff/beard on the face, and comb type: each of those traits should appear in at least some of his chicks and maybe in all of them.

You mentioned a Welbar hen. Since a Welbar hen has white barring, and that male does not, chicks will be sexlinks: sons will have white barring and daughters will not. So you should be able to recognize males at hatch because they will have a light dot on the top of their heads. The light dot is easy to see on black chicks, fairly clear on blue chicks, but if any chicks are other colors you may have trouble seeing the dot on them (light dot on light chick is hard to see, and some brown chicks seem dark enough but for whatever reason do not show the dot.)