I get my hay by the bale. so storage gets tricky for me. As well all know, rabbits much like horses can get very sick if fed "cow hay" this kind of hay sometimes has a bit of mold on it, and cows like it because the way they digest the mold doesn't bother them much. So all hay must be kept vry dry however it is kept. Living in a humid area trying to keep mold from forming is my main goal. I buy very large storage bins *the big plastic ones you store a large fake christmas tree, or large houshold items in* I keep two in my barn, and four in a small hay shed outside stacked on eachother. These have lids that snap down, it is not air or water tight but protected from bugs, and pests. I go to my local craft/fabric stores and buy a bolt or two of burlap fabric, and measure and cut lengths and place a piece on the bottom of the tub to keep sweating from happening and then a piece laid on top of the bale. You could do something similar with a smaller tub, and less burlap.