European Fibro Meat Bird Project

[Skyeknight]

Since about 10 August the white Hubbard has also started laying. She lays pink eggs and quite a lot of double yolkers at the moment. Furthermore I clipped the wings of both Hubbards, since they kept jumping the 1 meter high fence multiple times a day. They have stopped doing that. The barred Ross has been sleeping on top of the table with the Hubbards for about a week now.

I have done a "Fibro" test run so to speak with my Ayam Cemani rooster. This was the only rooster chick from a blue barred, white shanked hen. At birth he had a light coloured beak, comb and legs, which have darkened up later on. He had as expected in contrast to his sisters a light skin colour, but darkened up even though he carries 1 allele for barring and 1 for dermal inhibitor. Sadly he died the beginning of August at about 6 weeks old. I decided not to do an autopsy because of biosecurity reasons. But I do wonder if his meat would have black splotches. Guess I will still have to wait until next spring to try some more, this time with the CX pullets.

 

[Amer]

I do want to discuss the genetic side of things, especially concerning their feathers colours and patterns. I want to understand this so that I will already know what their offspring will look like/carry. This post will be about the Ross 308 pullets. I will discuss the Hubbard JA757 in a few days, since there is more information on their genetics available.

First it's important to understand what strain the parents are. This wasn't easy to find and I am still pretty confused on if they are Ross 308 on feed restriction or different parent strains also named Ross 308. There are sources that seem to be conflicting on this, which I will list at the end.

All sources seem to agree that both parents are dominant white, dominant white inhibits black feather colour but not the red/brown colour. As far as I am aware there has never been a Ross 308 broiler with red leakage, this means that they can still carry a lot of other colours and patterns beside red/brown.

As I have recently learned very very rarely a Ross 308 will be fully grey (I assume they mean blue with barring). This in itself is already incredibly interesting to me, since as far as I am aware dominant white parents cannot get offspring like that. Although with literal millions of offspring there are bound to be some exceptions/mutations. What is even weirder is the specific Ross 308 I got. She isn't fully blue barred, towards her tail and on her wings the dominant white seems to showing. There are different angles on her in my previous posts.

@Amer I would love to hear your input on this! I always enjoy reading your posts and threads about genetics as I learn so much from those.

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Sources:
I have read the Ross parent stock management handbook a few months ago, so it's possible I haven't found every single bit of important information. But it seems to suggest on page 65, 72 and 135 that feed is being "reduced". While page 29 and 32 suggest unrestricted access to feed. It's probably also safe to assume they get different nutrients from their feed than the broiler Ross 308, but I am not welversed in that. Furthermore a male reduction plan is mentioned on page 82 - 89. While on page 52 - 55 both separate housing as well as housing males and females together is mentioned.

This article from the Dutch Animal Protection Agency mentions in the table on page 57 that both the father as well as the mother line are called Ross 308. It also says that the paper behind a paywell "Effects of low dietary protein and different allocations of food during rearing and restricted feeding after peak rate of lay on egg production, fertility and hatchability in female broiler breeders." says the following:
In the Netherlands, the majority of regular broilers and broiler parent stock are of the Ross 308 type. These broilers grow on average 60-65 g/d and reach their slaughter weight of 2-2.5 kg in 35-42 days. The parent stock have approximately the same growth potential as their offspring broilers, but live much longer (60-65 weeks). Because they live longer, they would like to become too heavy if they were to be carried out without restriction, which would have a negative effect on their health and reproductive capacity.

And finally a paper from Wageningen University and Research states on page 14: For the regular broilers mainly Ross 308 was used (95%), the remaining 5% consisted of Cobb and by-products (= Cobb and Ross 308 cockerels from the hen line and Cobb and Ross 308 hens from the cock line of broiler parent stock).

Of course you would need to confirm all this with breeding tests...

Dominant White turns black to white, but it can be a bit leaky. Leakage is much more likely if the bird has just one Dominant White gene (the color called "Paint" is an example of this), but leakage or no leakage can happen in birds with one or two Dominant White genes.

For the white Hubbard, she might be Columbian colored, with Dominant White turning the black to white. Or she might be genetically black, with the black turned white by Dominant White.

For the barred Ross 308, I would expect her to be genetically black (gene E, Extended Black), with white barring, and then Dominant White turning the black to white, but not doing a very thorough job of it. I think there's a high chance that she has just one Dominant White gene, not two, but of course you would need to test-mate to be sure (see if you get any black chicks, or just white ones. Chicks colored like either of these two pullets would be considered "white," not "black," for this purpose.)

I've seen other photos of chickens with that coloring, and I've seen it called "ghost barring." I don't know what causes it to look that way.

There is at least one thread talking about ghost barring:
https://www.backyardchickens.com/threads/ghost-barring-question.1610628/
But it doesn't seem to have actual answers, just people saying they don't really know.

All that works out to a wordy way of saying "I don't know much either"




This talks about raising males and female separately, from hatch up to breeding age.

Page 45/chart 43 talk about recognizing sexing errors during the period before males and females are put together.

"it is good practice to remove these birds whenever they are identified during the life of the flock. Ideally, all sexing errors should be removed before mating-up."

From the way they say it, I would guess that males and females are from separate strains, with slightly different qualities.

They talk about "removing" the mis-sexed ones, but do not mention putting them in the pens of the correct sex.

But I think they must be pretty similar, because it only says that "ideally" the wrong ones should be removed. I might expect a stronger wording, like "it is essential," if it was really important. So I think chicks from the "wrong" mix will probably be pretty similar to chicks from the "right" mix of parent strains.


I think they are given unlimited access in the first days, then they get restricted feed. There is talk of several different feeding systems, because not all farms will use the same systems. But it definitely talks about making sure that all the birds can eat at once, which is important when they have limited feed but would not matter if the feed was always available (for example, production layers are often given free-choice feed, and are expected to take turns at the feeders.)


I think they are raising them separately until they reach maturity, then putting them together. There is a bit of talk about putting the males with the females a bit gradually (some males at one point, then add more males a little later), rather than mixing them all at once when they move from the brooder house to the place they will live when they are breeding & laying eggs.

I don't read Dutch, but from a look at the table I would guess that there are two lines without distinct names. Calling them "the males used to produce Ross 308" and "the females used to produce Ross 308" would be clear enough for almost all purposes, even if the Ross company has different internal names for them (line xyzq or something.)

Comparing with what you say of the Hubbards, where several different lines are crossed in different way, I'm guessing the Ross 308 line is kept distinct from any other breeding lines the Ross company may have, so the male line and female line might be genetically distinct without having actual separate names. But that's a guess.

Oh, here is something else:
https://aviagen.com/eu/brands/ross/products/ross-308
This page says the Ross 308 comes in both a fast-feathering and a slow-feathering version.

That means they must have at least two lines of parent stock (two feathering speeds).

I'm just discovering this thread. (I was absent in June.) It's very interesting!
I agree with NatJ
I think your blue barred bird is an extended black with barring with only one copy of dominant white. Ghost barring is common in birds with one copy of dominant white.
Probably some of its ancestors had just one copy but they were also recessive white or blue or something like that, so the breeders bred them forward thinking they matched the uniformity standard, hence the offspring turned out with only one copy of dominant white.