Spay cats and dogs...my family members and I are pretty much all for it! But for a chicken? I've never heard of that before... But I agree with MysticChocobo...it may kill your hen. Just like it's extremely rare for people to spay female horses, as it can be very bad for them unlike felines and canines, it is probably the same way with chickens, I'd imagine.
If you don't want eggs, why get chickens? Or, more specifically, why not get roosters instead of hens? There are lots of nice roosters/baby cockerels needing good homes, too (since more people want pullets and not the cocks, understandably, though).