Your best chances are within the first 24 hours after ovulation, but there is still a small chance two days after. So, honestly, if your ovulation really did occur on the 18th then your chances aren't that great because you would be past that 24 hour window, but I wouldn't say its impossible.
Cryptosporidiosis. Cryptosporidiosis is a parasitic disease that affects quail, pheasants, peafowl, waterfowl, chickens, turkeys, finches and psittacines (such as parrots). Cryptosporidia are poorly host-specific and can affect other animal species including humans, other mammals,...
Chicken Diseases: Prevention and Diagnosis. When raising chickens, just like with having any animal, we eventually will face chicken diseases with these birds of some sort. There are many chicken diseases that can effect your flock. We can prevent some, but some may be connected to genetics or exposures prior to your owning them. Purchasing vaccinated stock can possibly help you avoid troubles. Although vaccinating may destroy the organic value of home raised chickens for food.