I have one that uses 2 AA batteries and 9 little LED bulbs, I can see into the egg, but it could be brighter. I would go for one with 20 or so little bulbs. I dont know the lumens. Any hardware store or walmart should have them.
Get one that focuses the leds to one point. I've got a 9led flashlight but the bulbs all point straight out to make a wide beam and it doesn't work at all for candling. I have 2 different sizes of maglights including one with just 1 bulb that work pretty well. My favorite is actually a 3led cheap flashlight from walmart that has a really narrow beam. I got it years ago so don't know if it's still there or what exactly the brand is. It's just plain black, mostly rubber coated, wide and short base with a battery pack that holds 4 or 5 AAA batteries.