brother rooster and sister hen breedable?

[justin&shelley]

I'm about to have our first rooster in our flock, I bought what was to be 2 female week old Moran's and I think one of them is a male.
we don't want to have a rooster, I don't think. But it makes me wonder if they breed and have chicks is this like if family members
of other animals groups breed together and cause genetic problems?

 

[Kevin565]

As for breeding I would suggest against breeding brothers and sisters. It won't most likely cause issues the first generation but in later generations birth defect can occur.