It looks like a shell-less egg, but is it soft or firm? The diet you are feeding does not sound very good for egg laying. Is that scratch grains mostly? Do you feed a balanced chicken layer or all flock feed? Do you have crushed oyster shell available? I would make sure that she is getting a balanced chicken feed as most of her diet. Limit treats. For a few days I would offer a human calcium tablet with D3 to see if her shells become hard. I have had hens occasionally lay a tiny egg. If increasing calcium and a balanced diet don’t help, then she might be suffering from salpingitis (inflammation of the oviduct) or a defective shell gland.