So your advise is to buy a motion sensored light and hook up an alarm.That cat will disregard a light very quickly when it realizes there is no threat associated with it. Lights and noisemakers will only cost you money and more dead chickens. Been there, done that! Security lights though, CAN be used to alarm you that the cat is out there.
Buy the cheap motion detector double security lights. http://www.homedepot.com/h_d1/N-5yc...&keyword=motion+detector+lights&storeId=10051
Point the detector in the direction the cat has been travelling. Instead of a bulb in one of the sockets, screw in one of these receptacles that you can plug a cord into.http://www.amazon.com/Leviton-125-2...1411&sr=8-2&keywords=light+bulb+socket+outlet
With one of these you might be able to have the light also. http://www.amazon.com/Leviton-1403-...1411&sr=8-1&keywords=light+bulb+socket+outlet
Run the cord into the house to a buzzer or radio. Here is a buzzer. http://www.buzzersdirect.com/produc...-buzzerbr-part-number-12pn31100-ul-recognized When the motion detector sets off the "alarm" , you go out and kill this cat. The other light in the fixture will provide you with enough light to see what you're doing.
Do a YouTube search for "trapping bobcats". There is some excellent instruction there. Live, cage type traps have been a terrible performer for us.
Tariqjawed83. You mentioned neighbors close by with lights coming on. Do you live in town? Are you able to shoot within city limits? I guess I would shoot this cat if it were after my chickens...yes...ultimately. As I mentioned before, he could get accostumed to the light.