Question from my 8 year old. HELP! lol

[Sharedspirit]

My 8 year old daughter tonight asked me if chickens can be twins. I told her that because they looked alike, that doesn't mean they are twins. She said no, she wants to know if two chicks can hatch out of the same egg. I didn't know! I told her I'd find out for her if she'd go to bed. I'd never thought about it.

 

[Guitartists]

They cannot (usually) as they cannot share one air cell at hatch and have nothing to push against to hatch properly. And that's IF they make it that far. There is one member here who hatched twins.... but it's like a one in a million kinda thing.

 

[Kev]

I think identicals are impossible for birds. Besides the airspace.. The yolk is a limited supply unlike placentas in mammals plus birds absorb the yolk in one piece so if identicals are on one yolk that is probably going to be a huge barrier to identical twin hatches.

Fraternal twins are possible in birds.. two babies from one double yolked egg.. successful hatches overall are very low however it is "relatively common" in pigeons with human aid.

So I'd say identical twin birds are pretty much impossible, fraternals from double yolkers are common IN eggs, but successful hatches are very low.

 

[tororider]

I could be wrong but wouldn't they be identical if they were from a double yolker? Two babies from the same egg? I have seen several people on here talk about hatching double yolkers although from my understanding it is a rarity. Technically wouldn't all eggs that are from the same hen and rooster hatched at the same time be fraternal twins? I am probably wrong.

 

[Sharedspirit]

toro, I am so glad you asked that about eggs from the same hen and rooster! My 8 year old is quick and I bet she asks me that one too!

 

[Dodgegal79]

No they stil wouldn't be indential. They would have been fertilized by the same sperm, which is not possible in a double yolker egg. There would be 2 sperm involved, which would carry different genes.

 

[Kev]

Right, two sperm and two yolks in a fertile double yolked egg. Not identicals, it would be the same as two regular eggs.

Two chicks from a double yolker can even have two completely different fathers(sperm from one roo fertilizing one yolk, another roo's fertilizing the other yolk).. in that case they would be half-sibling twins.

Eggs in a clutch are all siblings, just the same as anything else. Nobody considers puppies in a litter "twins" even though they gestated and were born at the same time.

Fraternal twins is really just a term for more than one baby at a time for a species that normally has only one at a time, like humans, chimpanzees, horses etc. A double yolk egg could be considered twins as it's the "exception". "Fraternal twins" are not normally used for species which normally have multiple babies at once.. such as cats, dogs etc.

Identical twins is quite unusual and can be used for any species, even in a dog or cat- they can potentially have identical twins amongst normal siblings in a litter.

Some species of armadillos are very unusual in always having identical offspring- the nine banded armadillo supposedly always has a quad of identicals at birth.. one embryonic egg splits up into 4 embryos.

 

[d.k]

* So, does that make successfully hatched twin chickens valuble due to rarity-- or not???? (scratch head)

 

[Kev]

No, just "cool" due to rarity of successfully hatching two from the same egg. Otherwise they would be exactly the same as any two birds hatched from two eggs..