A few years ago I helped a professional geneticist work on his hobby project -- a similar project on the crested mutant gene in zebra finches. He mated crested x crested to try to get homozygous crested of both sexes. Then he mated the possible homozygous crested to a normal of the opposite sex. When normal offspring occurred, he marked that possible homozygous crested as a known heterozygous crested. He ended the project with 25 matings that produced either normal offspring or both crested and normal offspring. Zero matings produced only crested.

My point is that 5-10 matings are insufficient for the statistics.