chaffinch with one foot

chaffinch with one foot

Observation - chaffinch with one foot . Description: Saw this female moving oddly on the ground under the bird table,and at first was looking at the white tail feather.I then noticed that it only had one foot and the other is missing on the right leg it does look healthy enough but is it a accident or maybe

Saw this female moving oddly on the ground under the bird table,and at first was looking at the white tail feather.I then noticed that it only had one foot and the other is missing on the right leg it does look healthy enough but is it a accident or maybe birth defect ? help or suggestions please,have started putting food down under the bush for it so not as vunerable to preditors.