Araucana side project question

[flyingmonkeypoop]

We have had araucanas in the past and the tufted rumpless birds look good and all but I always liked the tailed tufted birds better. We are thinking about getting more araucanas in the spring through purchased eggs. I have finally talked the family into keeping the tufted tailed birds.
My question is what if we kept the tailed tufted birds and bred them together, would they breed true? I am thinking that they will because when they created the tufted rumpless birds they crossed smooth faced rumpless with tufted tailed. Also if I remember correctly the lethal gene is due to the combo of tufts and no tail, is that correct?

 

[klf73]

Quote:
I haven't had them long enough to know about the tail but I do know that the lethal gene is associated with the tufts, no where have I read about the tail having anything to do with it. I have hatched more tailed than rumpless (at least 75% tailed). My last hatch of 2 were both rumpless and only 1 slightly tufted, parent stock were both rumpless and tufted. I think the whole breed is very unpredictable

. Now I wonder if you started with tailed tufted and worked on your own line, culled all the rumpless and clean faced, if you would eventually get the tail to breed true. I don't know if the tuft will breed true if you work on it because all the breeders I know have clean faced birds to reduce the chick mortality. But I wonder if after many generations and many culls if you could get the tufts to breed true (but would have a very high chick mortality). Maybe someone that knows which genes are dominant would be able to help.......

 

[orcasislandchickens]

I am certainly no expert, but I believe the tufted to tufted cross is the one with the lethal gene, while the rumpless gene is responsible (due to the physical shape of the female interfering somewhat with the male's ability to fertilise her) for fertility problems. Combined, these traits make for reduced hatch rates.

 

[amazondoc]

What Orca said.

It's the tufts that are lethal. The rumpless trait just decreases fertility.

 

[flyingmonkeypoop]

Well darn it, I was hoping it was the combo of the two. I was noticing when Hinkjc crossed a smooth faced tailed with tufted tailed they got 50/50 tufted and smooth face. Is this the statistic most of the time with that cross? Maybe I can just keep tufted tailed birds and cross them with smooth face tailed birds.

 

[amazondoc]

Here's how the calculation goes. Remember, this JUST applies to averages -- not the exact percentages in each hatch.

1. there is no living bird with two copies of the tufted gene. So:
2. Tufted bird = 1 tufting gene ; clean faced = 0 tufting gene
-- I don't know the official notation for these, but for now let's call em T (tuft) and c (clean)
3. tufted x clean = Tc x cc
4. offspring will be Tc Tc cc cc = half tufted, half clean

5. Tufted x tufted = Tc x Tc
6. offspring will be TT (dead in shell) Tc Tc cc = 1/4 dead in shell, 1/2 tufted, 1/4 clean

So you actually maximize percentage of tufted offspring by mating tufted to tufted, but you will decrease the number hatching successfully by roughly 1/4.

ETA: as I understand it, occasionally "clean" faced birds actually have small unnoticed tufts -- so this may throw off the percentages.

 

[wilds of pa]

a bit here on rumpless
http://www.browneggblueegg.com/Article/Rumplessness.html#gene