My 2000 Ford Taurus se just lost all of it's anti freeze at one time for no reason.we think it's a hose but we are not sure.whats your best guess?

It depends where it was leaking from but most likely it was a hose , was the electric engine fan working before this happened/was the car overheating or it just lost the antifreeze try to find the hose and replace it then refill with antifreeze and let the engine run while your sitting inside the car watch the temperature gauge and listen for the engine cooling fan to come on if it does then you probably had an old hose if it doesn't then the engine overheated and the hose blew out if this is the case the sender that turns on the engine fan went bad or the fan motor itself went/to check the fan motor run a wire from the positive battery cable to the fan and see if it works if not check the fuse if it's good and the motor doesn't work it's no good if it does work but doesn't turn on by it self the senders no good in any case changing all your hoses so they are all new will be better so this won't happen again

It is probably a hose and all you have to do is add some water and see where it comes out. Another possibility is the water pump seal.