The Plymouth Rock Breeders thread

[racertomtom]

Been thinking. Always thinking, I guess. I have two chess plays next year. One is to breed the 75 to 75 and see how stable the current mix really is. I know I want to do that and will do that. But, I could also make some 88 Piano Key birds.

My guess, however, is that the 88s will not be made. Why not? I don't want the birds to have 88% of their original foundation line. So, the chess move there would be to another line altogether, a line in fine shape. So, the result would be real blend that will take 3 years to stabilize and that's a big project. The gene pool would be really stirred up, eh?

If I do nothing other than breed the 75 birds to each other next year? I'll be fine. We'll see if my palms start itching long about October. LOL

I am assuming the GS line was a slow maturing line even with vigor restored. I’ll be watching the GS/Stukel and GS/Duckworth birds very closely.

Your progress has been very impressive, especially with the fast maturing traits that you apparently got from the Main line (looking at aoxa’s line). I’m concerned that if you keep going back to GS birds you will eventually return to slow maturing birds. The question is, what is there to gain from the GS line that you don’t already have? Not much in my opinion. Whenever I’m unsure or curious, I’ll do both.

 

[Fred's Hens]

Haven't decided, Jill. If I ever will.

The questions I ask myself are these. What needs to be done? Do they need more size? Do they need better egg laying? Do they need to mature more quickly? Is the barring what it needs to be? Are the heads, or tails, or breasts so hideous that these issues must be addressed? What impact upon the birds, over-all, would be an unforeseen or unexpected consequence of adding something else?

 

[Fred's Hens]

I am assuming the GS line was a slow maturing line even with vigor restored. I’ll be watching the GS/Stukel and GS/Duckworth birds very closely.

Your progress has been very impressive, especially with the fast maturing traits that you apparently got from the Main line (looking at aoxa’s line). I’m concerned that if you keep going back to GS birds you will eventually return to slow maturing birds. The question is, what is there to gain from the GS line that you don’t already have? Not much in my opinion. Whenever I’m unsure or curious, I’ll do both.

Your assumptions are correct and your concerns about going back again to make 88's is precisely why I won't do it.

 

[Yard full o' rocks]

Here is a Jan hatched cockerel I am watching closely. Pix makes him look a tad bit "rainy day backed" but he is truly quite flat backed. Hoping his front end fills in completely and I see the hint of a lifted tail!!

 

[Silver Rock]

41 more eggs went into the incubator last night so with any luck I will have more Silver Penciled Plymouth Rock chicks to add to my count in 3 weeks.

 

[emenheiser]

Tom is correct. When I breed the 75 together next year, (and I will) they'll still be 75s.

To be really, really honest, I like these proportions of blood. The only reason to "add" something more to this line would have to be narrowly defined and focused for a specific reason.

You bred two varieties in your 75 and 87.5 birds. I did not. I simply refer to the ratios of the lines used. Hope that helps.

Sorry, genes don't work this way. The "percentage blood" system was once used commonly to describe genetic composition, most famously with the case of Spanish Merino sheep. But then Gregor Mendel came along (1866) and helped point out the fallacy of the early "blood" system. That was almost 150 years ago--it's time to move on.

Green paint is a mix of 50% blue and 50% yellow. Mix equal proportions of that green paint with the original blue, and you will get blue-green paint that is 75% blue and 25% yellow. Mix equal proportions of the blue-green paint a second time and the "offspring" will still be 75% blue and 25% yellow.

But genes are not paint. Each parent contributes a random sample of only half of their own genes to the offspring. This is Mendel's Law of Segregation. Mate two "75" birds together, and the offspring can theoretically contain anywhere from 0 to 100% of their genes from the original line.

A "75" does not even reliably contain 75% of the original line's genes when a "50" is mated back to a purebred! Those offspring can range from 50-100% of the original genetics themselves.

How true the 75 birds breed to the "blended" phenotype is mostly a reflection of how close the original lines were in genotype to begin with. It also has a lot to do with which genes were sampled in the F1 and the first backcross. Those birds that are more homozygous (containing a a higher percentage of genes from one of the two lines) is more likely to breed true to form.

But no "line" is a fixed and constant thing. Every individual within the population contains a different sampling of genes, and the populations themselves are constantly evolving as segregation interplays with selection, drift, mutation, etc.

So, to be perfectly clear, the labels like 75, 88 etc. may be helpful in describing the matings that were used to produce the birds, but they are essentially meaningless when it comes to describing the genetics they contain. This is even more true when the breeder steps away from backcrossing (to a pure line) and begins inter se mating, i.e. when hybrid birds (e.g. 75s) are found on both sides of the pedigree.

 

[Fred's Hens]

Thanks Joe. That's great stuff. Thanks for taking the time.

Money quote: Mate two "75" birds together, and the offspring can theoretically contain anywhere from 0 to 100% of their genes from the original line.

This. True. We do tend to use 50/50 and 75 as off hand, colloquial expressions, describing what we've done, but such expressions are not technically accurate descriptions of the genetics involved and how they are at play, as you rightly point out.

 

[Fentress]

When you cross lines, I have heard that it is helpful to increase the hatch as much as possible, so you can make the best selections and get going in the right direction as soon as possible. For people who show or have a schedule they want to adhere to, this would be important. But for someone who does not, how important is it to get off to the best possible start. Can you eventually get where you need to go, making good selections, but with low numbers, say 50 - 75 per year. I don't have the experience or facilities to do this yet and have not even evaluated the Duckworth stock that I have now, but the Maine line that has a quicker grow out does seem to be a good idea, at least for me. I hope people continue to maintain this line so it is accessible at some point in the future. I am enjoying my birds, they are getting bigger and starting to show a little type. Been looking at their heads to see who is the widest and have a serious look to them, if that makes sense.

 

[Matt1616]

 

[gjensen]