Had one of my young rollers born with "bull" eyes. Thats what they used to call one that had all dark eyes,they seem to be bulging since they are all one color. Not that uncommon except this one is also blind on one side. And I don't think it sees all that great on the other. It always stayed on the floor and never moved on up to perching and flying like the rest. I thought it was sickly and finally caught it to examine it. Thats when I discoverde its problems. I've had bull eyes hatch before and never had problems ,hope this is just a rare case and the pair doesn't do it again. Will have to watch them closely now.