I have found a crow fledgling with white feathers? What does this mean?
If you find a grounded premature rook or crow with white and partly broken wing and tail feathers, then this is often caused by a nutritional deficiency. These birds need expert longterm care to allow the damaged feathers to be replaced during their first complete annual moult.
Birds affected should not be released before their complete annual moult, which happens for fledglings in the summer of the following year. Otherwise it is unlikely that these birds will survive their first winter, as the plumage will quickly deteriorate further, which means that the birds will become grounded, getting easily wet and hypothermic, and are unable to sustain themselves.