ya know.. i can't say for sure because i don't know for sure, never saw this one before
but... i can't imagine that it wouldn't be okay, as long it was safe hay [type of hay--tim etc.] i mean organic just means that no chemicals, no pesticides.etc.. have been used.. and that is the way we have to go for herbs for them, wood..etc.. its the safe way. so i can't think of any reason why it wouldn't be good.. as for the color, isn't hay naturally yellowish, i mean you drive down the road and see a farm with hay bundles rolled up and they are always yellowly. and i want to say that i think i heard someone say once before that they dye hay.. and if that is true, then the hay we normally buy wouldn't be so green... but more of the color hops sees...
so again, i'm sorry thats the best of my opinions.