if a hen is infertile will she still lay the eggs with nothing in them or will nothing happen

She will lay infertile eggs as far as I know

It is rare for a hen to be infertile. It is also actually quite rare for a cock to be genuinely infertile (as opposed to not in season as the testicles shrink/shrivel up when the males are not in season but while they are technically not producing sperm, they are simply out of season rather than clinically infertile). Often infertile/clear eggs result from males being out of season, or in season but not mating properly.

 

I have heard very few cases of hens being infertile and having checked semen myself from 'infertile' cock birds and found it full of live sperm I believe many 'infertile' cocks are simply cocks that lack the drive/personality or have missed the opportunity to mate successfully (poor perches, box bound hen, nervous hen, vicious hen etc etc).