chupacabra problem?

I'm a rancher in SE California, in the foothills of the Sierras and driving distance to Mexico; longtime lurker here, first time poster. Anyway, I've been having what may very well be a super natural or at least unique and unusual experience. We keep chickens for eggs near the house and have had a streak of them disappearing from the coop at night. Thinking it was a simple case of Coyote, we built a little coop up on stilts for em and put in a 4 foot tall chicken wire fence to keep the little bastards out, but that still hasn't stopped one or two chickens from vanishing a week! Further, if it was Coyotes I would expect to find the hole in the fence through which they entered, the bones, beaks, feathers and other un-digestables or at least HEAR when the animal was getting to the hens but never find any sign. Old Mexican man working for me figures its a chupacabra, one of their local superstitions south of the border, but sounds to me just like a hairless, rabid dog-- how could it have cleared my fence or made off with a hen without making a sound?? Anyone else got any ideas what could be stalking my ranch, or any theories that don't involve aliens at least, lol.