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I’ve been wanting to do this for a LONG time and it wasn’t until recently that I started the process of breaking this down. This will be a series of posts with picture examples embedded as links as well so I hope this is of help for both new players and old alike. As always, I am always open to questions and comments or even specific requests to explain something!

To understand possible colors of horses you are thinking about breeding or for that ultimate color you aren’t sure just how to maximize your chances of getting, you would start with the base color of the horse: black, bay and red. These 3 colors are the basis of which every single color combo on this game originates from. They are formed by extension and agouti. Extension is represented by the initials E or e and agouti is represented by a or A. They work hand in hand and they should always be considered an unit.

So far we have:
Black: To get a black horse, your horse must have one of the following genotype:
EE aa
Ee aa
(agouti must always be recessive and there must be at least 1 dominant extension- there is not a phenotypical difference between the different combos of black)

Bay: To get a bay horse, your horse must have one of the following genotypes:
EE Aa
EE AA
Ee Aa
Ee AA
(agouti must have at least 1 dominant copy and there must be at least 1 dominant extension- there is not a phenotypical difference between the different combos of bay)

NOTE: This does not take into account the different types of agouti on this game: this will be addressed in a different post

Red: To get a red horse (also notated as chestnut on the game), your horse must have one of the following genotypes:
ee AA
ee Aa
ee aa
(extension must always be recessive- agouti status does not influence)

Now something to keep in mind is that you might see genotypes written as eE AA or EE aA or ee AA. The order does not matter to the color of the horse- the order in which it is written tells you which allele was passed on by the sire and dam.

That is, the first letter for each gene represents the allele from the sire and the 2nd letter in the gene is the allele from the dam.

Take for example this genotype: Ee aA

This is a bay foal (1 copy dominant extension, 1 copy dominant agouti). This foal inherited E and a from its sire. The dam contributed e and A. Without looking at the genotyping of each parent, you can immediately write their genotypes as such:
Sire: E_ a_
Dam: _e A_

The blank spaces are to notate that you do not know their other info yet. You can see how both sire and dam can influence the color of the foal depending on what they contribute!

Let’s up it a little more: in the case of our bay foal whose genotype is Ee aA, we have done more research and found out that the sire is black with 1 copy of recessive extension and the dam is red with 2 copies of dominant agouti. We would write it as such:

Sire: Ee aa (Remember, it only takes 1 copy of dominant extension and 2 copies of recessive agouti to create black)

Dam: ee AA (again, red is not influenced by agouti status, only presence of 2 recessive extension alleles)

The sire can pass on either E or e (50%) and will always pass on 1 copy of a (because there is only 2 copies of recessive agouti)

The dam can only pass on 1 e and 1 A.

If you do all the possible genotype combos using a Punnett square, you’d have a list like this:
Ee aA (bay with one copy of dominant extension and 1 copy of dominant agouti)
ee aA (red with 1 copy of dominant agouti)

This cross had a 50/50 chance either way of a red or bay foal. A common mistake is to look only at extension and say "oh this horse can make red, bay, and black babies because they have one copy of each!" They do not take into account the agouti status of their horse. Because the mare can only pass on a copy of dominant agouti, a black based foal (E_ aa) can never be produced from this cross.


I am going to wrap up this post with one final "quiz" question regarding potential foals from a cross.

True or False Thishorse and this horse can only produce bays. Explain your answer.

Everyone who answers, correctly or not, will get a little gift sent to them so please feel free to put your thoughts down- if not comfortable putting your answer here, you can direct message me!



Again I hope this is helpful and I will start elaborating on the other colors and how they work in conjunction with the base colors to create the rainbow of horses we have here on HaJ! Requests will also be considered if you have a particular color combo you want to understand better!