the type of pneumonia you are referring to by the lay term "walking pneumonia" is either viral or caused by an organism called mycoplasma. the pathogen (germ) that causes the pneumonia may be contagious but the person who is exposed may not get pneumonia. either their own immune system will fight it off or the particular germ or the exposure may cause something other than pneumonia like a simple cold. the bottom line is that you are not very likely to get pneumonia.
can you catch walking pneuammonnia from being with them on the farm always?