Chick with genetic defect

[u/Significant_Snow_718]

[u/Away-Wave-2044]

This one has….evolved

[u/_who-the-fuck-knows_ → u/Away-Wave-2044]

This is kinda how evolution works. Random mutations in genes. The good mutations carry on through breeding.

[u/cipheron → u/_who-the-fuck-knows_]

Not just that, it shows how other genes can get repurposed in the process. It didn't have to re-evolve front legs: they're clearly reusing the genetic code for the back legs to create front legs.

So, often it'll be one small mutation that has an outsized effect because it repurposes other genetic machinery to do something complex.

[u/henkheijmen → u/cipheron]

Yeah or in this case more likely an anomaly where some cells were displaced at a very early part of development. This is more likely a form of conjoined twinning than it is a genetic change.