I just tested in Creative and can't find any way to do it wrong.
Even if I threw them way beyond the render distance of chickens they were waiting there when I ran over.
It's hard to keep track in Creative since you don't use up the eggs but I was getting at least one chicken per ten eggs on average though I did have a run of 30 eggs with no chickens so I suppose 100 isn't entirely impossible. I agree it does seem unlikely though.
What version are you running, for those that know about the differences.
There are a couple of bugs in the bug tracker that could be relevant but they mainly seem to be for very old versions or the Bedrock edition.
What are you throwing them against? If you are throwing them on a fence post, a chick will not pop out. Ever. (personal experiences) They will only pop out if an egg is thrown against a full block. (eg: Grass Block, Dirt, Wooden Planks) They will not pop out if thrown against a block that is not full. (eg: Fence Posts, Hoppers) There are a few articles on Gamepedia: Gamepedia Article on the Egg, and Egg Farming Article. Check them out. They might help.
I always count - Chickens, from Eggs - from Stacks (16 Stack-together, of such). Generally, since it takes me at-least 4 - so 64 - Eggs to be more-or-less guaranteed - wait for it "A" Chicken (Chick /Baby Chicken initially) - all I can do is Hope I don't kill it basically-instantly by hitting-it with Further, Thrown Eggs (takes only a few).