My hen is making a odd calling sound. I'm not totally new to raising chickens but a couple weeks ago we had babies roughly 3 months old who were all murdered by what I think was a fox since I had spotted one across the street two days prior to the attack (we had 7 chicks) she (our hen) made this weird sound early in the morning and I found 5 of my babies in the yard dead and the other 3 were gone. This afternoon she made another call (same one) and I immediately rushed outside but nothing was there. Could something be stalking my hen??? I refuse to get anymore chicks until our fencing is reinforced and more protected but I just wanted another opinions?