Rule number one for employees: the boss is always right. Always keep that in mind.
The others are laughing because she is the boss. It doesn't mean they think she is funny or that you are dumb.
I suggest you teach yourself to say "What a good idea." then go home and raise your chickens any way you want to.
I would never discuss poultry at work. If the boss ask about your birds, simply say that your spouse has taken over and you don't know what is going on with them, nor do you care.
Your boss's behavior is really inappropriate. Keep smiling and start looking for a new job in your free time. This is not a good economy, so it is not a good time to quit without another job lined up. Be pleasant, work hard so you can get a good reference.
When looking for a new job never ever, not ever, say anything bad about your old boss. Just say you are hoping to find a more interesting job, or it's time to learn a new job skill, or you are hoping to find something closer to home, or you need better health coverage for your family. Think of a reason that doesn't make you look like a complainer or a malcontent type of employee.
Best luck to you.