You have not ruined anything.17 out of 23 hens have either no crop or squishy crop. I dont know what to do I'm so lost. I am so scared. I don't want to start over. I ruined everything and dont know how to fix it.
You don't have to start over.
Now. Let's take this one step at a time.
When you say they have "no crop" and "squishy crop" when are you feeling the crop - the time of day is important when you feel the crop.
A crop should be empty or flat first thing in the morning before a chicken has had anything to eat or drink.
Feel the crops at night when they go to bed. Take out the food/water from the coop.
Go out first thing and feel the crops again, they should be empty.
IF they have access to food/water before you go out there in the morning, it's going to be very hard to gauge crop function.
The flicking of the heads - did you also clean out your coop, bedding and nesting boxes and treat the whole coop for lice/mites?