Will an eeBb dog always have a black nose?

Not if he's also dd. And there can always be poor/incomplete pigmentation in any color dog.

Yes he will at some point in his life have had black pigment. We all know that yellows can and often do have poor pigment as they get older or they get winter nose and the pigment fades, but at some point in its life, as a puppy there would have been black on his nose, eye rims, pads, lips, etc.

The dd or dilute gene does not exist in the general population of Labs Nancy and therefore I do not care to discuss its effects on coat and/or pigment color.

And should this eeBb dog be bred to a chocolate that does not carry yellow(EEbb) the resulting litter will be black and chocolate since the B allele is dominant and those puppies inheriting the E allele from its chocolate parent will make black (EeBb).

This is just simple genetics. I'm sure the simply silver person will come on here now that the dilute gene has been introduced or someone else will argue about how genes can mutate and what not. But since those occurrences are extremely rare, to answer your question simply yes at some point that dog had black pigment, but if it fades, it may tend to look brown or turn pink altogether. Look at the pads, lips, etc for where there may still be black pigment. And when in doubt, VetGen offers DNA testing

Does an eeBB dog get winter nose also?

Not interested in dd or other breeds.

Yes, there are other modifying alleles that control the intensity of the black pigment. Nancy is partially correct in that it is located at the D locus. However the general population of Labradors do not carry the d allele which is responsible for dilute colors. There are also other alleles located at the C locus that control the shades of yellow and chocolate. But for argument sake and to keep it basic, we generally just focus on the E and B locus to understand how we get black, yellow and chocolate.

An eeBb and eeBB are phenotypically the same, the eeBb just carries the allele that restricts black pigment (b). Hence when paired up with another b allele, you will either have chocolate or yellows without black pigment (NBP-No Black Pigment). This is why it is so important to know what type of pigment is behind the yellows in the line.

Regardless of whether they carry chocolate, black pigment depends only on what is in the pedigree.

Should except for winter and age.

If you read the Blue Knight color chart, eeBb x eeBb litters have 25% no black pigment puppies. So you would not want to breed an eeBb to another eeBb. The eeBb dog should have proper pigment depending on the pigment behind him or her. Some lines have better pigment than others.

I have an eeBb who had great black pigment until she turned 6, at 10 she's a little lighter. She got a winter nose yearly but each year it came back to full black by early summer and her eye rims and mouth never changed, pitch black. One of her yellow daughters has never had a winter nose and remains black 365 days a year and she's over 8 years. I don't have that with every yellow. It's an extra plus in my opinion.

If you have an eeBb you should stay away from breeding to Eebb, chocolate carrying yellow. Look at the chart at Blue Knight Labs. That chart can be helpful when in doubt. Thanks to Di Welle for the usage of it on her website.