$4, but people try to pay me $5 and even $6.  I wouldnt MIND charging more, but I know my older customers couldn't afford it, and it wouldn't be fair to charge one customer more than another.
Why so high, you ask?  The farmer's market is a half-mile from my house.  They charge $6+ a dozen for organic eggs.  Most of my customers come over and HOLD my chickens--sometimes they bring their kids over to feed them.  These are the customers who try to slip in the extra $1 or $2.   Perhaps they feel they need to support the "petting zoo"?