Depending on how long they have been incubating, they are probably non-viable eggs. It is typical that you have some ratio of viable to non-viable brine shrimp eggs. Incubating the non-viable eggs further will not yield any additional hatches. Many suppliers offer "premium" products with a higher viability rate, but the standard offerings typically have a large portion of non-viable eggs.
I run the air pump for 48 hour hours on my hatches to make sure that any viable eggs hatch. Obviously, after that, any eggs that don’t hatch I consider not viable. I do this because I found that 24 hours was not sufficient. I would always end up with an excessive amount of unhatched eggs.
You’ll get a few extra ones hatching. I always got a better hatch rate after decapsulating them. This also allows you to feed the unhatched ones, as they have no shell. Bit of a faf, decapsulating though.
I tried this a couple of times but found the unhatched eggs yielded no extra shrimp and to the best of my knowledge there is no use for these, meaning a food source for tank inhabitants. As was mentioned, most producers list what the success rate is for hatching because there is always a percentage that aren't viable.
