Question about inbreeding.

[MysteryChicken]

The most probable answer is that it's a developmental thing - It's not uncommon to get "runts" - some of which thrive and some of which don't.

if "every" chick in that project group was growing out smaller and smaller, that's when you start looking at your stock genetics.

She was like everyone else, as little chick. She was similar size up until I realized she's not really growing. Maybe there's a Bantam/Dwarf gene somewhere?

I have had runts before, but she doesn't fit that bill, since she really hasn't had problems growing up. My runts usually grow up full sized, but take longer to grow.

 

[DarJones]

Work on the method of inbreeding. Uncle/niece is typically half the intensity of a brother/sister or father/daughter mating. First cousins mated together have more risk than second cousins. Second cousins have more risk than third cousins. All stabilized breeds of chickens are the result of inbreeding. It is a tool the breeder uses to stabilize and concentrate desirable characteristics.

Getting one deformed chick from a mating is only informative if a large number of chicks are hatched. Outcrossing usually gives a very low level of deformed chicks. Inbreeding - whatever the intensity - has potential to show recessives which may include deformities. My suggestion would be to repeat the mating and try to hatch 20 more chicks. Pick the very best from this mating to produce the next generation.

However long your birds are maintained, eventually you will reach a point where outcrossing is desirable. This should be carefully considered and an outcross line obtained that has most potential to bring new and useful traits while minimizing undesirable traits.

Size is highly determined by genetics. If you get a small bird from a normally large breed, I would cull because the breed standard is not met. This doesn't mean there is no use for such a small bird. Maybe you want to breed a small Orpington that is between bantam and full size.