How do you know eggs are safe to eat?

Most of the time eggs you have recieved from your chicks that you raised are more safe then store bought eggs. That being said you can get it from any eggs. If you cook throughly then that kills the bacteria.

Keep your chickens healthy.  Keep their area clean, their food dry, and their water fresh.

It happens more with caged animals that are wallowing in their own poo, or the poo is what they eat, sleep and bathe in. In factories, they have mountains of poo under the wire cages that hold the chickens. Humans have to suit up and wear masks when they go in, to not breathe it......and they will occationally clean it out if there is a samonilla scare or spray the mountain of poo with chemicals......SOme factories are getting better on sanitation, but noit many as, more work=paying for more man hours, and as you can tell, eggs run cheap.

If you have healthy birds and a healthy coop, giving then Apple cider vinegar in their water (look online for measurements) and they have pro-biotics to add in or already in food, your hens will be happy and healthy. I guess there is really no WAY of telling, unless you have a chemistry lab in your house and you test the poo, chickens vents and eggs themsleves... So good luck! LOL!!! I feel VERY comfortable eating my backyard chickens eggs....Don't stress so much and enjoy your eggs, they are SOOOOO good!!!!

No homeowner-easy way, no.  If you'd want to know if it's on the surface of the egg, you could do a swab and then culture, isolate, stain, and ID any bacteria.  You're going to need access to a microlab and some associated knowledge, though...or a willing wallet and patience.  If you'd want to know what's IN the egg (because salmonella is sometimes found inside eggs), then you'd have to crack it and go through the process described above.  Pointless, because then the egg is ruined and you'll not be eating it anyway.

As others have said, if you keep your chickens and the areas they inhabit clean, harvest eggs regularly (e.g. don't let them sit around long enough to get dirty), wash your eggs, and thoroughly cook any eggs you use, you'll be fine.

Keep your birds and their quarters clean and cook the eggs properly and all will be fine.