Percentages of different breeds in my crosses

yeah it is lol its kind of the foundations of a breed im making, Easter eggers/ameraucanas for colored eggs, silkies for skin color,crest, feathered legs and eventually feather type, cornish and jersey giant for body size, and leghorn for egg size, longer tail feathers and such eventually i want to get a large bird with silkied feathers, feathered feet, crest, black skin, pea comb, beards, ameraucana shape with a deeper breast etc.

so if I breed these two together what do i get?
25% jersey giant 12.5% leghorn 3.125% ameraucana 3.125% cornish 1.5625% easter egger 54.687% silkie


25% jersey giant 12.5% leghorn 53.125% ameraucana 3.125% cornish 1.5625% easter egger 4.6875% silkie

I know this is a lot of math and i cant get my head arround it at this point

so i got this: 25% jersey giant 12.5% leghorn 28.125% ameraucana 3.125% cornish 1.5625% easter egger 29.68725% silkie
how does that look?

Actually, you can take any percentage less than 50% and throw it right out the window, because genes don't work that way. Genes are packaged into chromosomes. Chromosomes come in pairs; one member of the pair came from the mother, one from the father. Sometimes, chromosomes in a pair may "swap" parts with each other, but most of the time, chromosomes get inherited intact. A chicken has 78 chromosomes. Even in a cross between two purebreds, slightly more than half of the genetic material may have come from a bird of one breed, slightly less from the other (because the pair of chromosomes that determine gender are very different sizes). When you breed a 50/50 hybrid, you have no idea how many chromosomes from which parent get passed on - they may line up in any combination.

An example of what I am talking about - most people are aware that a mule is a cross between a horse and a donkey. It is generally accepted that mules are sterile, but there have been several female mules that have given birth. In one case, the father of the mule's offspring was a donkey, and out of curiosity, the owner had the foal DNA tested. The results showed that the mule's foal was 100% donkey. It had (obviously) gotten donkey chromosomes from its father, but though it could have gotten horse chromosomes from its mother (which was half horse), in this particular case, it didn't. Some mule's foals have tested as part horse, part donkey; but the percentage doesn't necessarily work out to 75/25.

With the complex crosses you are talking about, it's quite possible that some resulting offspring will have no genetic material at all from some of their "ancestral" breeds, if the purebred birds are far enough back in the cross.

that is interesting thank you

If you're trying create a breeding population with a few specific traits, I suggest choosing one feature in particular and line breed for a few generations to establish that particular gene. Then pick another trait to add and line breed back to establish that gene while still keeping the first trait, and so on. You need to be very careful to only breed birds with the specific traits you want. To get to the point where you have a flock of birds with the desired traits that consistently produce similar chicks, will take many years of very careful breeding.

well the dominant traits such as fibromelanosis are very easy to breed for as well as blue/green eggs

If you're mixing in brown egg layers with your blue egg layers, you're going to get green/olive layers not blue. If you want blue eggs, you will have to work to get the brown egg gene bred out. I'm not sure it's even possible to remove it from a line, once it's been introduced.

im going for more of a mint green than a blue