Is my black Silkie E or ER?

[Cloverr39]

I'm starting to question if my black Silkie rooster is really based on E/E. I read that extended black based chiks are typically all black, while ER/ER chicks have white markings on the face, chest and tips of the wings, so I'm wondering if my rooster might’ve been ER/ER this whole time. Apparently ER based black birds are more prone to leakage, which checks out, as he does have a bit of silver leakage and two of sisters had leakage as well if I remember correctly. Is it possible to make a good guess to what his color is based on chick down?

Sadly, I don't have a picture of just him as a day old chick, just one of his sisters and a group photo of all siblings. I do have one of him at 2 weeks though.

1st picture: his sister.
2nd picture: all of his siblings, including him somewhere.
3rd picture: him at 2 weeks old.

 

[Amer]

You have it backwards. E/E chicks actually can have more white on the belly and face than E^R/E^R based chicks, but this isn't always the rule because E/E chicks can also be solid black. It's impossible to tell birchen and extended black down apart.

 

[Amer]

If his sisters have some silver it does make a birchen base more likely since E/E hens are likely to be solid black without help from modifying genes.

 

[Cloverr39]

You have it backwards. E/E chicks actually can have more white on the belly and face than birchen based chicks, but this isn't always the rule.

Whoops, my bad

It's impossible to tell birchen and extended black down apart.

Ah, alright then. I was just trying to figure out the genotypes of my Silkies for fun and got curious. Some of my black chicks are solid and some have lots of white, so I was wondering if that might have something to say about what they or their parents might be based on.
But if they're impossible to tell apart from down, are there any ways to tell them apart at all?

 

[Cloverr39]

If his sisters have some silver it does make a birchen base more likely since E/E hens are likely to be solid black without help from modifying genes.

I realized I accidentally confused chicks from two different years. His sisters were solid black, but two of his daughters had silver leakage. Sorry about that. That would make it more likely he's E/ER, wouldn't it?

 

[Amer]

I realized I accidentally confused chicks from two different years. His sisters were solid black, but two of his daughters had silver leakage. Sorry about that. That would make it more likely he's E/ER, wouldn't it?

Well, I imagine is his sisters were E/E^R they'd still be solid black. But if it's not much leakage he's more likely E/E^R but it's really hard to know.

 

[Amer]

https://birdgenetics.tumblr.com%2Fpost%2F755109963281694720

I do think the very defined white patches might be a birchen trait but I'm not sure.
https://www.cacklehatchery.com/product/birchen-cochin-bantam/
(Eta realized my links are messed up on the post)
If you look at these birchen Cochins, the chicks can have that defined pattern or a lot of white.