I think it says 'use within 7 days of opening' on the bag.
I don't know about the signs of it going off exactly, but again, I think it says what to look for on the bag. I feed it very rarely, so I'm a bit useless I'm afraid!!
providing it's fairly cool you should get it to last at least 7 days, if not a bit longer (10 ish). Its pretty easy to tell when it has gone off, smells a bit skanky and/or you see mould or really wet patches on it
You will find the colder it is the longer it lasts, small bales should be used within a couple of days, when it starts to turn it will start to smell more and sweat, also you'll see flys will be attracted to it, if it goes like this, dispose of it!
[ QUOTE ]
if you take it out of the wrapping and open the sections up keep it out of sun light and rain it will las quite good!
[/ QUOTE ]
I do that too, I take it all out, sprinkle and fluff it up, dry it out like hay and then use it, only do it with the little bales if I need to use it up for it turns, rather than wasting it.