Are you collecting them from the wild? Its possible that you could get a few albinos if the color mutation exists in the area. The parents would have had to been heterozygous for albino though(assuming its a recessive trait).
Yes, I'm collecting them from the flowerbeds around my house. I try to rearrange them every year as the females tend to place their oothecas next to each other with leads to the babies eating each other instead of the nuisance insects; I ended up with over twice as many oothecas as last year and still have more to collect.
I'm not sure how the color morph genetics work in mantids, so I guess I'll just wait and see if I get lucky.