One of the problems in the commercial broiler
Hi Anonymous, I would imagine you could get some pretty horrible mutations using an xray machine on eggs, especially in the earliest stages. I know with human pregnancies the earlier the xray, the higher the possibility of gross abnormalities.
The commercial Cornish-Rock cross is not the same as a cross between say a show Cornish and a Barred Rock. They have been selectively breeding this cross since the 1950s and are light years different in genetics from the original breeds. It used to take 12-15 weeks to grow a 3.5 lb bird. If you can keep the modern broiler alive you can get a bird of over 4 lbs in 5-6 weeks.
Thank you for your post, Rokimoto. I am aware that
industry is that the Cornish Rock cross have a
relatively high post-natal mortality. I have the
sense that they are just not hearty birds. Just
sneeze in the broiler house and several will fall
over. What is responsible for this phenomenon?
Lack of disease resistance? Do they die from
heart disease? Stroke? (One of my jobs when I
was a kid was to go help pick up the dead
chickens that died overnight in the broiler houses.)
Of course some illness, like avian pneumonia, are
facilitated by the living conditions.
It seems to me that one could tolerate a slightly
lower growth rate (feed conversion) in exchange
for a significantly lower post-natal mortality. Have
any readers here crossed cornish with other birds
to judge how they perform? To assess that, one
would have to keep careful records.
A different subject, has anyone ever tried to
intentionally induce mutations.... for example, by
putting eggs in an X-ray machine? We did that with
beans as a 7th grade science project years ago. It
helped that one of the kid's father was a radiologist
at the local hospital.
By HannahH on Sunday, December 2, 2001 - 11:10 pm:
The reason is in the earliest stage of development there are fewer cells that can be damaged by the radiation. The fewer the cells, the more the damage, since all of those cells eventually evolve into the more complex structures of the body later in development. You probably already know this, just thought I'd throw it out there for anyone who may not.
I enjoy your posts Anonymous!
By Rokimoto on Monday, December 3, 2001 - 03:09 pm:
There are several factors as to why modern broilers have a high mortality if they are not cared for properly. Selecting for the rapid growth rate seems to have compromised their immune systems. Broilers put less energy into fighting off disease then a normal bird and more into building muscle mass. They also grow too fast, and a lot of times their hearts or other organs can't keep up with the rapid growth. You don't need hormones or antibiotics to get them to grow. It is all genetics. What is a common practice is to restrict their feed so they grow more slowly. This sort of defeats the purpose of getting them to grow so fast, but fewer birds fall over dead if you don't have them on full feed. They probably have people figuring out the pennies. You might take longer to get to market, but you have more birds to sell if you slow them down a few days.
By Anonymous on Monday, December 3, 2001 - 03:23 pm:
commercial broiler programs often are willing to
pay tens of thousands of dollars for a single bird if
they believe it can fit with their breeding program.
And, i am aware that commercial lines are closely
guarded secrets....although it is possible to patent
a chicken, often a company will NOT because the
act of patenting is tantamount to disclosing. It is
sometimes better to maintain a corporate secret
than it is to patent.
I have an opportunity to participate in the formation
of a poultry producers co-operative. I won't say
more at this point, but I was just curious about the
actual causes of death, because I know that those
commercial Cornish Cross hybrids are delicate
and are not hearty birds. I didn't know if it was
immune system function, cardiac problems, or
what.