How to differentiate Australorp chicks from Australorp x IsaBrown

[Goddess Sekhmet]

Hi all,

I recently ran a small batch of eggs from my girls - 4 pure Australorp hens(about 5 months old) and 8 Isa Browns (or Hylines?), with a pure Australorp rooster.

They've started hatching, and there seems to be a good mix of yellows and blacks - can I assume the black ones are purebred Australorp, or do Australorp/Isa mixes ever come out with full black fluff?

Picture attached (blurry sorry)

Thanks in advance

 

[NatJ]

It's a bit late, but if you're still trying to figure this out:

I would expect the ISA Brown hens to produce about half yellow chicks, and about half black chicks.

If you want to be sure, separate the hens into two pens and set one batch of eggs from just the ISA Browns. If you hatch any black chicks from ISA Brown eggs, you have proof that it's possible.

As they grow up, any black ones with an ISA Brown mother will probably have some red or white color show in their feathers, and thus look different than the pure Australorps.