The Plymouth Rock Breeders thread

[emenheiser]

I agree with the intended point of the post. 75% of a line when out crossing or 75% of a male/female when line breeding does not mean that 75% of the offspring’s genes came from that gene pool. I do think however, that more than a hundred years of selective breeding practices have proven that it greatly improves the odds that the random gene selection will come from those gene pools.

I'm having a hard time wrapping my head around the first statement; in my simple mind, it suggests that it is possible to hatch a giraffe, which I find highly unlikely. I suppose you mean 0 to 100% of the line they're 75% of.

I don’t think labels like 75 are essentially meaningless, just an ineffective way of describing the odds. Which can’t actually be described or calculated.

Actually there are ways to calculate the probabilities, as well as molecular genetic tools to discern exactly what percentage of an individual's genes came from a particular ancestor.

The problem is that past a certain point, genetic composition is more or less irrelevant to describe the complex type traits that are important to standard bred poultry. I would probably even argue that most of the discussion about 100 year old lines is past that point as well.

Of course the longer a population is selected toward the same goals, the more isogenic it becomes. But on the other hand, with selection based entirely on phenotype for complex genes, any and every gene and gene combination that results in that phenotype is selected, and that serves to preserve genetic diversity. Selection for vigor at the same time is also largely selection for heterozygosity, and that too slows the process of homogenizing the line.

But to make the 75% comment more clear, if a Ringlet line bird is crossed to another lines, all offspring contain 50% of their genes from each of the two lines. but when those F1s are backcrossed to the Ringlet line, the 50% of their genes that they contribute to their offspring is randomly sampled. On average they will contribute 50% of the genes from both parental lines, making the offspring 75/25, but this is only an average. They could contribute anywhere between 100/0 and 0/100, making the offspring anywhere between 100/0 and 50/50.

If two of those 50/50 "75"birds happen to be mated together, it is possible to create offspring with 0% Ringlet genes.

As I said before, the biggest limiter of the variability in these crosses is if the two lines were fairly genetically similar (to each other) to begin with. How standardized the two lines are (within themselves) is important, but not nearly as much.

 

[Fred's Hens]

Just by phenotype, what we SAW, at the 50/50 stage, the chicks produced where admittedly rather random and somewhat scattered in terms of consistency in type, feathering, color, etc. Not too surprising.

This year, at the "75" stage, we are seeing an amazing level of consistency in the chicks. The "clone-ish" or what we farmers might call a level look was honestly quite exciting. Of course, we've still got to grow these birds out to a fuller maturity.

 

[Fred's Hens]

I can see the camera caught this pullet stepping away, but I still like the pullet on the left. I've seen your older hens and I'm sure this pullet will follow true to form and her tail will be outstanding later on.

 

[Fred's Hens]

How much older is the bird in the foreground than the bird standing by the corrugated metal back there? Age difference is what? 3 weeks or more?

 

[Fred's Hens]

I'd like some opinions on this barred cockerels he is the most promising one I have so far he was hatched on Christmas day. Thanks

Can you tell us more? Did you breed these birds? From parent stock you own? Hatch from eggs from someone?

 

[dreamofglory]

Can you tell us more?  Did you breed these birds?  From parent stock you own? Hatch from eggs from someone?  

yes I bred them myself.

 

[alana124]

I just have to say, these last few posts (2 + pages worth) have been so informative ...thank you for the excellent reads and points to ponder.

 

[Fred's Hens]

Gonna be a long day here, After a few overcast days with some showers, the sun is out clear and bright and the cockbird seems to be singing a special aria to rejoice. Lots to catch up with. Lots of weeding and hoeing. A little early to do all the 400 fall kole family transplants that will need to be done, but I see the plants are nearing that point. (cabbage, broccoli, cauliflower) Noticed the predictable potato bugs are preparing to lay their eggs.

Dug a 12" deep hole to take my sub-soil moisture tests. Not great, so irrigation will likely be back tomorrow.

Got to move some chicken tractors and rotate release times. These chicks go from having dull, almost white legs to sparkling bright yellow/orange legs soon after they're put out on the grass. It is always an amazing thing to witness. While the Barreds dodging in the shadows of the oak trees and the White Rocks pasture on the deep green grass making a stark contrast that makes me feel good inside.

Joe Em mentioned true being "type plus function/purpose". Yeup. The Plymouth Rock. Here? That means a farm bird. It's a beautiful morning in the country. Good to be alive. Have a great day friends.

 

[Silver Rock]

How much older is the bird in the foreground than the bird standing by the corrugated metal back there? Age difference is what? 3 weeks or more?

Hi Fred, the 4 in this picture was all hatched in April. The cockerel was setting down behind the three pullets. The pullet in the foreground was larger at hatch and has continue to pull away from the other two pullets. I really do like the way she look and hope she continues to fill out nicely.

 

[normanack]

Do these look like White Rocks to you? 1930s: