In hopes to help others better understand the breeding of the fibromelanistic gene, we have created a breeding chart.
The fibromelanistic gene is represented in one or two copies. Each bird will express the gene differently. In some cases, a one-copy bird will express in such a way that it appears to have two copies, especially when the gypsy face gene is present. This can explain why some that have two very fibro expressive breeding birds may not produce all fibromelanistic birds.

If both parents have only one copy of the gene when bred together, your offspring will be:
- 50% 1 copy fibro offspring
- 25% 2 copy fibro offspring
- 25% non-fibro offspring
If 1 parent has 2 copies and the other only 1 copy then they will produce:
- 50% 1 copy fibro offspring
- 50% 2 copy fibro offspring
This can obviously present difficulty and frustration in breeding unless a person takes the time to breed in order to find out how many copies each bird has.
Possibly the best and quickest way to do this is through test breeding your fibro bird to non-fibro bird. For instance, a 2 copy bird bred to non-fibro bird will yield a 100% 1 copy offspring. While a 1 copy bird bred to non-fibro will only yield 50% 1 copy fibro offspring and 50% non-fibro offspring.
The goal in getting darkest birds is to find out which birds are 2 copies and breed then them together.
You cannot make a judgement of how many copies they have by appearance alone as some 1 copy birds will be more expressive when gypsy face gene is present, while some 2 copy birds may be less expressive when gypsy gene is not present and although having 2 copies of fibro they express in mulberry instead of black.
The true test is breeding.
I hope this helps and takes some of the frustration away from those who are just getting started with breeding this fascinating fibromelanistic gene.
And I would be glad to answer any questions in the hope of helping you with bettering your breeding program.
Article written and picture developed by Cliff Charles Simmons and used with permission