The hay crop last year varied hugely from area to area. Also if you buy from these online places you have no idea if they are actually selling you 2011's hay...which was really not great, we had a lot of problems with the horses early 2012 as the stuff cut late 2011 was pants.
We stopped using our normal hay man for some time and were getting hay brought up from Sussex, however he brought down a bale of his late 2012 crop and it's beautiful stuff, so the ponies and piggies are back on that.
As I have said to people countless times on here, a well stored and cut bale of hay is far more economical and better for your pigs than all this plastic wrapped crap. Hay is not designed to be wrapped in anything, silage and haylage are wrapped either a day (silage) or 2 - 3 days (haylage) to keep the moisture and sugars in, hay should be baled and left unwrapped but is often covered in something like thin material if a lot of birds nest overhead etc. By wrapping it up in plastic bags you encourage it to 'sweat' and trap more sugars in, it also ends up softer which is worse for their teeth.
Do yourselves a favour, buy one of these
http://www.amazon.co.uk/dp/B0058IBU...and=692206625691677348&hvpone=&hvptwo=&hvqmt=
And ring up your local horse feed merchants and ask them questions about their hay...where is it cut, when was it cut, can you come and see a bale and most importantly choose your own. You store it in the hay bag, with the top open, so the air can circulate, I take out a section at a time and keep it in a big tub trug to kart around from hutch to hutch at night. Ideally you would remove it from the bag and store it on something like a wooden pallet, so off the ground so the air can get all around it, with a light blanket on top, but appreciate not everyone can do this.
Hay is anywhere between £3 - £6 a bale depending on your area right now, and a bale lasts me with my 18 1 - 2 weeks, it lasts my mum with just 3 around 6 - 8 weeks.
I am afraid I just cannot get my head around people who have this information but still pay the earth for a teeny tiny bag of hay that hasn't even been stored properly, that they have no idea where it has been cut from, when you could save so much and get a better quality product.
Pig007, I don't even spend £50 a month on hay and I have a horse on restricted turn out to feed as well as my gang! That would buy you 12 bales!