no eggs who had them?

Rats

If you keep poultry you will have rats and you will get overrun if you you don't do something about them. A cat is essential - preferably an outdoor cat, underfed. Try to keep anything rats will eat (that's almost anything including live chicks) out of their reach. Make sure no chicken food is left out at night. You will still need to have a go at them once in a while and poison - unpleasant though it is - may be the only way.

First there were 4 eggs.

then a couple of hours later there were none.  

It had to be rats

Mouse traps work very well for small rats - this kind is easy to set.   Big rat would laugh at it.   You can get rat sized versions - I haven't tried them and anyway big rats seem very intelligent and don't walk into traps

 
This an even bigger rat trap (not set) - it's designed to be used in a rat box (see below) - the rat jumps onto the plate and ....... very difficult to set without losing a finger and I never caught anything.

 
wooden box is a trap box, plastic one is a poison box.

 
wooden  trap box, but used for poison - important thing is that chickens or wild birds can't reach the poison.

 
box designed for poison and can be use outdoors - needs a locking mechanism for safety, this one is difficult to use.

 
rats don't only eat poison - this plastic dustbin had wheat in - we only use galvanised now.

 
and this is a pot of rat poison - a kind that didn't work - maybe he knew.