If I found a blood spot on an egg, do I have to remove the whole egg or just the blood spot?
The general rule regarding our eggs nowadays, is that even though our eggs are non fertilized and it would technically be permitted to remove only the actual blood spot, however it is still preferable to remove the whole egg. It is not clear to me what case you are asking about, because you wrote “remove the whole egg or just the blood spot”, that sounds like the egg was already mixed with other eggs etc. If the egg was mixed together with other eggs and you can’t remove it, then all the eggs are permitted. Therefore if the egg were mixed with other eggs and you can tell which egg yolk ha the blood spot, then it should be removed. However the white part of the egg, which you can’t discern which egg it is from, would not have to be removed.
Minchas Yitzchok 1-106, Igros Moshe Y:D 1- 36.