legal or illegal?

I am living in Maryland. I have a small area where I can do my gardening and a space for my animals. Recently, I wanted to buy some chickens so I can have a few fresh eggs. I told my neighbor about it and he said he would have me turned in to the city if I did it. Why? Isn’t it legal according to any property rights law for me to do whatever I want within my residential real estate, right? What do you think I should do to solve the problem?