exactly that. An egg that has not been fertilized. This is typically done between a male and female of the same type. Ex: Chicken and Chicken; Frog and Frog; Catfish and Catfish; and the list goes on.
an egg that cannot be fertilized therefore cannot hatch
When there has been no contact with a rooster for at least 10 days.
It is almost impossible to tell a fertile from an unfertile pheasant egg just by looking at it. If you hold it up in front of a bright light, in a process called candling, a fertile egg will show a dark spot inside and a network of red blood vessels within the egg.
Chickens don't get pregnant. Unlike mammals birds release their ova for development outside of their body. Chickens will produce one egg every day even when it does not come near a rooster. The hen produces that egg automatically, and will drop an egg even when it is unfertile.
Never.
Well, when I tap my nestboxes they immediantly get out, unwilling to even attempt to protect their clutch from me. However, if you mean the sense of a male lovebird protecting his offspring, then yes. Lovebirds or any bird will think the egg is fertile even if it is infertile or a dummy egg. They usually reject the egg once they sat on it for a week or two.
If she looks like a guy
arable means refined .. an antonym will be unfertile
Nothing will usually happen. The hen will scream and peck at you to get away but that is about it. It wont make the egg unfertile or make the hen abandon it (only in extreme cases it will).
Not being able to get pregnant is what being unfertile, or infertile means - so no. However, nature can be a bit tricky, and apart from a couple of medical conditions it's quite hard to say when the chance of pregnancy has disappeared entirely.
I have raised blue mystery snails for a few years and I have never seen one lay eggs when they were the only snail in the tank. I have seen egg clutches that didn't hatch, but I attribute that to an issue of the environment and not the fertility of the eggs.
yes they can, if there is no male, or if perches are not stabile, than mating can be unsuccessful
That's commonly called either sterilization, or a vasectomy.