I bought a new bag of Ings Meadow Hay as I ran out, which is their favourite and they have it daily, but they've hardly touched this new batch!

Is it because of the time of year/they're picking on grass and leaves etc? The hay looks the same as always, maybe a bit greener than usual - it smells delicious if you ask me! Should I be concerned and try to get them something else? It cost me 18 so I won't be best pleased if they waste it!