We have had our 4 laying hens for only 8 days now. On day day 3 we had an egg with a bloody shell and every day since there has been a little on one egg. I just checked the girls vents and one of them is all bloody. I didn't get a close look but it didn't look good! She is still laying and eating and doesn't appear any different to the other hens. Should I be worried? What should I do? Thank you!!