My dear Sir

I want much to beg your assistance; but it will cause you the loss of a good deal of time, & probably you will have to make enquiries from other breeders.

I know that you will not answer without feeling sure, & will permit me to give you as my authority. My queries relate to the colour of the first plumage of fowls after the down is shed. In fact I almost require a description of the colours of each breed in the first plumage; & as the sexes are I believe at this period always alike one description will serve for both sexes. I will specify some particular points that you may see my object, which is quasi-embryological. Chickens in their first plumage of all white & black breeds are white & black, & the adults of both sexes resemble each other. Now what is the colour of the plumage of the chickens of the cuckoo sub-breeds, of Dorkings & of other breeds, & of the Sebright bantam, for these several sub-breeds & breeds are nearly alike in colour when adult. If the chickens are not like the adults do they acquire the colours of the adult plumage earlier than games, Malays &c of which the 2 adult sexes differ greatly in plumage.

What is the character of the chickens of the Pile Games, & are the hens when adult white where the Cocks are white? I am especially curious about the chickens in first plumage & about the hens of the Piles.

What is the colour of the chickens of Golden & Silver Spangled & pencilled Hamburgs & of Spangled Polands? What is the difference between a chicken of a Golden & Silver spangled & pencilled Hamburgh in their first plumage?

(N.B By chickens I always mean first plumage after the down is shed.)

At what age can the young cocks of the various sub-breeds of the Game (Red & Black breasted, Duck-wing &c &c) be readily distinguished; i.e. at what age do they acquire their characteristic colours? Are the young cocks alike at first?

I have arranged on a separate slip of paper, as far as my ignorance permits, the several breeds in order, beginning with those in which the adult sexes do not differ in colour of plumage, & ending with those which differ most; & I think you will best understand the chief object of my enquiry when I say I want to know whether the age at which the colours of the adult plumage is first acquired approximately corresponds in order with this list. Thus the black & white breeds at the top acquire their colour very early i.e. at first, & Games & Malays comparatively late in life. Now at about what age do such breeds as Golden pencilled Hamburgs & Partridge-Cochins, which do not I think differ in colour sexually so much as Games, acquire their adult colours?

I have expressed myself badly throughout this letter, but I think you will see that I want to make out, viz the relation between sexual difference in the colours of the adult plumage, & the period of life at which the adult masculine colours are acquired.²

I shall be particularly obliged if you will employ as much of y^r time as you find necessary to give me full & accurate answers to these troublesome questions.

My dear Sir | Yours very sincerely | Charles Darwin

Pray forgive excessive untidiness of this letter, but I am overwhelmed with letters & work, too much for my small strength: otherwise I would have rewritten it.

If you can answer partially in regard to some few of the breeds, soon, it would be a great assistance. & I sh^d. then be able to judge how far subject worth pursuing.³