They mean a day old chicken that has hatched. They are comparing a human embryo to a live chick.
If it is a male chicken that is not going to lay eggs, it will get shredded
To my knowledge they do not have an inexpensive way, let’s be honest any way that costs any money is probably not going to be used unlessed forced, to find the sex of the chicken before it is hatched.
It’s called chick culling if your interested in reading about how 7 billion male chick’s get shredded each year worldwide.
It’s “I can excuse animal cruelty, but I draw the line on abortion”