New to hatching, and having bacteria issues.

[Chip_Chip_The_Rooster]

I had noticed the mama hadn'tbeen laying on the eggs anymore, and 3 daysago when I went to go check on everybody I found a broken egg with a baby chick, and ants crawling all over the poor thing. Thismorning after moving the 3 remaining eggsto my room with a heat lamp anddehumidifier, I had noticed a rotten nastysmell in my bathroom, where I had been keeping the eggs, so I had done some research after candling the eggs to try and see some type of movement or heart beat I saw nothing, I tried the float test again nothing, so as a last ditch effort I had tried topre pip one of the eggs, i had tapped very carefully where I had marked the air sack, and the egg blew up! With this nasty pus looking blood every where!!! I read that if the egg blew up while doing this that it was most likely from bacteria.
So my question is, how do I keep my new eggs from mama hen, from getting caught by this bacteria? This is my first hatching experience, and I do not own an incubator. I have one egg from the last batch that has a small black spot in it floating around, and picked up a new egg today. Any information would be helpful.
After putting the new egg under the heat lamp yesterday i decided to candle it this morning to find a little moon in it.

 

[AnnieSantiago]

Could have just been a rotten egg.
The hens often know when the eggs are no longer good.

 

[Chip_Chip_The_Rooster]

Could have just been a rotten egg.
The hens often know when the eggs are no longer good.

Well she had been moved from one house to another, I've been told that she would stop laying on them because of the new home.