Hybrid VS Pure

[Mitsos Lamprogiorgos]

Is it true that hybrid chickens are much more robust and hardy than the pure ones?

 

[sylviethecochin]

Depends on the breeds you're crossing. Depends what you mean by "robust and hearty." Hybrid vigour exists and is strong, but studies have shown that "labradoodles" are more likely to develop hip dysplasia than either labradors or poodles are.

There are two facets to hybrid vigour, and I stole the descriptions below from Wikipedia:

• Dominance hypothesis. The dominance hypothesis attributes the superiority of hybrids to the suppression of undesirable recessive alleles from one parent by dominant alleles from the other. It attributes the poor performance of inbred strains to loss of genetic diversity, with the strains becoming purely homozygous at many loci. The dominance hypothesis was first expressed in 1908 by the geneticist Charles Davenport.[4]
• Overdominance hypothesis. Certain combinations of alleles that can be obtained by crossing two inbred strains are advantageous in the heterozygote. The overdominance hypothesis attributes the heterozygote advantage to the survival of many alleles that are recessive and harmful in homozygotes. It attributes the poor performance of inbred strains to a high percentage of these harmful recessives. The overdominance hypothesis was developed independently by Edward M. East (1908)[5] and George Shull (1908).[6]

Dominance hypothesis is traditional hybrid vigour. Overdominance hypothesis is closer to CornishX or Sexlinked layers.

 

[birdofhermes]

that seems to be a general rule of reproduction in any species. i can say that my own rooster is a lot more robust than others that i see people breeding for shows. people seem to have a lot of trouble with diseases and aggression in purebred dogs so maybe purebreds are just inbred to a larger degree

 

[sourland]

Great post by @sylviethecochin. The answer is 'it depends'. In the hybrid sex link egg layers, the hybridization has dramatically increased egg production but also resulted in a concurrent reproductive tract problem. In the rock Cornish cross, growth and feed conversion have been greatly increased but at the cost of long term quality of life. Other crosses can result in back yard birds that live forever.

 

[Eggcessive]

I would agree that in any animal if the gene pool is small, and some illness or defect gets into that gene pool, you are just going to breed bad animals or birds. It seems the current it chicken breed or dog tends to have more problems. I have always found “mutt” breeds of anything can be healthier. Chicken breeders tend to cull birds who don’t fit certain breed characterisitics, and if something does get into that line, it can result in perfect looking chickens who are not particularly resistant to disease or healthy. Same with dog breeders who line breed.
My mutt cats and dogs never seem to need vet care, but friends or relatives with expensive cats and dogs, tend to have a lot of health issues or deaths. All chickens have been mixed from time to time with other breeds to get certain characteristics, a certain egg color, or size. The bigger the gene pool the better the chances of a healthy chicken.

 

[lazy gardener]

Is it true that hybrid chickens are much more robust and hardy than the pure ones?

If you are talking about hybrid chickens in the back yard flock, I would agree. But, when some folks say "hybrid chicken", they are only considering the sex linked hatchery hybrids. In that case, I'd say definitely not.

 

[Folly's place]

In any breeding program, selection criteria matter, and often, health and longevity are not considered, or are very low on the list. Young animals are bred before issues develop, and difficulties that occur in middle or old age are very hard to avoid.
Most chickens are bred their first year, and culled by two years of age. That doesn't reward the individuals who would do well longer!
There's a fantasy out there that mutts live longer, and it's a nice thought, but not so true, and not at all relevant for each individual. Some dog breeds are awful aberations of what's healthy or normal (think English Bulldogs!), or are giants (Great Danes) and giants of any species have real issues.
Breeding healthy individuals to each other is critical, and now there are DNA tests for some genetic disorders of dogs to help breeders who care make better choices.
The longest lived and healthiest dogs have many old relatives!
Mary

 

[Folly's place]

My carefully selected purebred Chesapeake Bay Retrievers, and German Shorthaired Pointer, all with old relatives, lived to be twelve to fourteen. My shelter mutt dropped dead at four of a rare heart condition, and my shelter mutts all have health issues, and another died at age nine.
I'll continue getting shelter dogs with sad back-stories, but I'm not expecting stellar health.
Mary

 

[lazy gardener]

Young animals are bred before issues develop, and difficulties that occur in middle or old age are very hard to avoid.
Most chickens are bred their first year, and culled by two years of age. That doesn't reward the individuals who would do well longer!

Excellent post. I also consider 2 types of culling when breeding forward in my flock.

1. Hard cull: remove the individuals who are not thrifty. They may be early molters, or they may do a prolonged molt. They may not be as hefty as a hatch mate, not start laying as early, or not lay as frequently.

2. Egg cull: Simply set the best of the best eggs you have. When choosing eggs, I look for excellent quality eggs from gals in their second year of lay. If I have pullets who have admirable qualities, I will also set some of their eggs. The second year eggs that are not as thick shelled, not as large, or that I know are from girls that don't lay as frequently will not get set. Therefore, looking forward to future generations, in theory, choosing the best eggs will result in hens who provide better eggs than the past generations.

 

[Frazzemrat1]

When it comes to dogs, I wouldn't even say that all breeds vs mutts are less healthy. It depends on the background of the dog... My rat terrier, my screen name is named after her, never got sick, never needed a vet visit until she became geriatric. I ended up finally putting her down after dealing with kidney failure, doggie Alzheimer's, blindness and deafness; when she was 18. That's about the equivalent of a 104 yr old woman.