Mountain Lion once again

Several years ago 20 of my 22 sheep were killed and hauled off by a mountain lion. Then big dog and mountain lion got into a fight. Big dog won, although she did end up with a huge scar down her belly. I think that was five years ago. We haven't had any trouble with mountain lions since.
 
The neighbor was out walking along property lines and took a picture of this footprint next to my back fence. If you look at it right you will see a massive footprint (not the shoe, right next to the shoe).  This isn't of my dog!  I wish it was.   It's a big ol' mountain lion paw print.

I am going to have to come up with some sort of strategy to protect the sheep.  Locking them up in the barn is one way since usually the lion will attack at night.  The problem with that is that I travel and am not home each night to lock them up.  I could keep the sheep locked up all the time.  I'd have to feed them rather than they eat the pasture if that were the case.  They'd eat about $20 per week of hay.   I don't know if I would even break even when it would come time to sell them.  I don't want to lose money on the animals.  On the other hand, if I don't have any left because the lion kills them all then that's no good either. 

Even if I am home at night to lock them up, letting them out during the day may not be an answer either.  The last time the lion was so bold that it jumped over my 4 1/2 foot high fence at 3:30 in the afternoon, killed a ewe, put it into its mouth and jumped back over the fence and off to wherever it was going to take the kill.  That lion was so clever that the county trapper wasn't even able to catch it. 

I can get another depredation permit to try to kill it.  Any other suggestions, or anyone want to come shoot a mountain lion?