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Check the inbreeding coefficient of a pairing before you commit a cage to it. Wright's method, calculated across three generations, in your browser.
A coefficient is a probability, not a verdict. Here is how to act on each band.
Safe to pair. This is the range most unrelated or distantly related birds fall into. No special precautions needed.
Caution. Workable once to fix a mutation, but do not repeat it in the next generation. The risk compounds across seasons, not within one.
Measurable risk to hatch rate, chick survival and adult vigour. Find an alternative bird. Above 25% means full siblings or parent-offspring.
Below 6.25% is generally considered safe. Between 6.25% and 12.5% warrants caution and should not be repeated in consecutive generations. Above 12.5% carries measurable risk to hatch rate and chick survival.
25%. The same figure applies to a parent paired with its own offspring. Both are the highest coefficients you will encounter in normal breeding, and both are worth avoiding.
Lower is safer for vigour and hatch rate, but some line breeding at low coefficients is how mutations get fixed in a line. The risk is cumulative, so one 6% pairing matters far less than repeating it every season for four seasons.
Because most real inbreeding hides one generation back. Two birds with different parents can still share a grandparent, which produces a coefficient of 3.125% per shared grandparent. Without that layer you would read the pairing as unrelated.
Yes. Wright's coefficient is species-agnostic. The maths is identical for budgerigars, cockatiels, finches or anything else. Only the tolerance thresholds differ slightly by species.
No. The calculation runs entirely in your browser. Nothing is sent to a server and nothing is saved. Close the tab and it is gone.
KinBird works out COI from the parents you have recorded every time you pair two birds, and warns you before you commit a cage.