I am considering purchasing Araucana eggs for hatching. I understand that there is a lethal factor in 25% of the eggs layed. Is there a sex link to this factor weighted to pullets vs. cockerals or visa versa?

Jan,
Though I have never bred Araucanas (actually never seen one at 50+ shows) I understand the fatal recessive factor is associated with rumplessness. Purebred Araucanas have no sign of a tail whatsoever--if it has a tail it is a mutt. The fatal recessive factor works the same as the one associated with the short leg of the Japanese Bantam (Chabo) and the crest of crested ducks. In Europe there are rumpless Chabos--can you imagine the level of frustration?

John deSaavedra
breeder of fine Japanese Bantams

The direct answer to the sex linkage question is no. If it were linked to sex, it would easily be eliminated in one generation. Instead it is linked to the absence of tail.

My mistake! The lethal gene is associated with the tufts. Sorry for propagating this misconception.

John is correct the lethal gene is associated with the tufts not the rumplessness. Rumplessness means that the birds, both male and female, do not possess a tail. The entire coccyx is missing. The rumpless factor is one of the easy traits to breed for.
The tufts are skin projections that are heavily feathered that grow from the ear lobe region on the side of the bird's head. This tuft can be seen on a newly hatched chick. The true Arucana is very difficult to breed about one forth of the hatching chicks will be dead in the shell. Another one fourth will not have tufts-clean head. If you like genetic this is the breed for you. Had them for 20 years --
great fun

I was wondering if anyone out there has ever has a chicken lay an egg with out the shell.

I have nine hens that lay an egg each day. the last two days I found one very thin shell then the next day an egg that seems to have no shell at all.

I give egg producing food and oster shell to the hens. Is there something I'm missing that could be causing this problem?

Nancy

I get my information from Araucanas: Rings on Their Ears! by Cathy Brunson. She got her info from Ralph Somes of the University of Connecticut.

Tufts are due to a dominant gene (Et). It is not to be confused with muffs & beard, which is not lethal. The gene is lethal only when the unhatched chick receives an (Et) from each parent, and is therefore (EtEt). This can only happen if both parents have visible or non-discernable tufts. The results of such a mating would produce: 1/4 (EtEt)dead, 1/2 (Etet) tufted like parents, and 1/4 (etet)non-tufted birds. Professor Somes says that about 20% of the heterozygous (Etet) also die.

Ear tufts is not sex linked.

Are there any other lethal genes for Aracunas? This is my first time raising them, and i don't want them to die.
HorseSRme@aol.com

Every organism, including each of us, carries recessive lethal genes, which if randomly paired with a matching lethal, never develops to be born/hatched.
I know of no other "common" lethals in Araucanas.