Egg Problems/ hen problems?

[BackwoodsMomma]

Hi all. I am new to raising chickens. Our neighbor gave us 2 hens( 1 is a topknot, not sure about the other) anyways we put one of our roosters in with them ( a Beautiful Easter Egger) Sure enough she/ they accumulated 15 eggs before they both began setting on them,( they have always shared a crate and still are). Today, however when i went to feed them they only had 13, there was one on the ground with a hole in it, and I'm not sure where the other one went. Is this normal? Are they like dogs or cats and can tell if something is wrong with one and push it out? Our rooster is still in with them but never bothers them.. she makes a funny noise when you get near her also ( I'm assuming a warning..lol). They have been setting for 1 week today and by my calculations we are due little ones around the 11th or so of May. Any input would be much appreciated. Also if you need more Information just let me know. Thank You

 

[Silkies~Polishes]

Something must have taken the eggs, since one is just gone, and I don't know why a hen would really want to hide an egg. In my experience, my hens don't get rid of the bad eggs, I have to candle them and throw them out myself., I'm not sure if hens really get rid of the bad eggs, maybe it depends on the hen? So my best bet would be some kind of small predator, rat, or raccoon, or snake or something.