Keeping siblings

[NYREDS]

I have line bred a closed flock of Rhode Island Red Bantams for over 20 years. My fertility & hatchability are excellent, I almost never have a sick bird & my birds compete successfully in shows up to the national level.

 

[ravencreek]

Thanks everyone. I am no longer scared of having deformed chicks anymore. I was hoping to breed them but wasn't sure if I needed a new roo or not. Weight has been lifted.

 

[brandywine]

You have to consider the amount of background inbreeding in the birds to start with.

Two full siblings from parents who were entirely unrelated are not very inbred themselves.

Two full siblings from parents who were siblings, grandparents who were father and daughter, etc. -- you start running into problems with homozygosity.

This is not just "doubling up on undesirable recessives" but the general problem of inbreeding depression, which has clear effects on disease resistance, fertility, birth weight, longevity, weight gain, and productivity in all species. (How severe at the same coefficient of inbreeding -- COI -- varies by species and often by strain within the species.) Heterozygous animals, taken as a group, are always more vigorous than homozygous (inbred) animals.

If you are selecting a flock for production characteristics, easy-keeping, good health and longevity, err on the side of outbreeding. If you are selecting for fancy points, inbreed and cull is the fastest way.

In your specific situation, I'm assuming that you've no way of knowing the approximate degree of inbreeding behind your birds. So you have to make your best guess about the background inbreeding in the birds you have now.

You are probably just fine keeping the hatch-mates and raising young from them. I suggest that you swap out roos for the second generation -- when the birds you raise from your first generation hatched on your place are ready to be used as breeders, get new unrelated roos, don't use the fathers on the daughters.

But that could be years from now. It's good policy to get your hatching eggs from hens that have proven their productivity and good health for a couple years, at least. It doesn't matter if a roo is mating his daughters and you are eating the eggs!