How to make fertilized eggs unhatchable for an on premises farmstand

So I have 15 hens and one rooster. Yes I know the ratio isnt the best but it's what I have. My girls only free range in the afternoon for 2-3 hours a night and have a large coop and run. I live in Illinois and thats kinda important.

My rooster is fertile and the eggs are all fertilized. I have tried separating him with just a few hens and that doesn't work in the long run. My boy George gets stressed knowing there are hens he cannot see but can hear.

I raise hatchery quality silver sebrights. I do not want to flood my local market with low quality silver sebrights that are all related to my flock. I love my flock and do not want to expand or sell live birds or hatching eggs. I have a small project going of trying to breed/create show stock from hatchery stock but its very very slow and probably never going to happen lol. I keep all my birds and dont sell them. My oldest bird is 5 and she is also a sebright.

My farmstand has a mini fridge that I recently purchased and it works at optimum operating standards.

I have thought about washing them and refrigerator them to keep them from hatching but im not 100% sure on how to do it safely. I have tried looking up ways to do it safely or if I should use a very mild amount of soap when gently washing? Would just getting them wet, rubbing them a bit, letting them dry and putting them in the fridge be enough.

I have been feeding them their eggs back since March as well as eating them and giving them to people who i know won't hatch them.

Thoughts, opinions and advice are welcome.