While in confinement like this, the sows milk is lacking the iron that it needs to give to her piglets. This is because she does not have the natural access to the soil, which carries iron. You can easily prevent piglet anemia, by giving your piglets an iron shot. There are other supplements you can do as well, such as giving a pill orally. However, the shot is typically most effective since it is injecting strait into the blood stream.
With preventative measurements, piglets will live long and healthy lives.
Just remember that as an owner it is your duty to make sure that you are properly caring for your livestock!
Hogs and kisses!!!