When adding bedding, it really should be dry, clean straw, dry wood shavings, or dry pine straw. Hay should always be avoided for bedding because it molds so easily when it becomes even slightly damp. A primary purpose of the bedding is to absorb moisture from droppings, so using hay for bedding will always bring the secondary problem of mold. A large percentage of droppings will happen during the night when birds are on the roost, so when adding bedding, be sure to put plenty under the roost area. When you clean the building, you might leave a 'dry corner' or two, but always clean carefully under the roosts for this reason. Henhouses and runs need to be as dry as possible as much of the time as possible. Inside the house, bedding that doesn't crackle any more will need to be changed soon. If your birds are confined, the only way for all that water they're drinking to escape is through egg production, respiration, and droppings. There must be carefully controlled air flow at all times to help draw off moisture and gasses. Lingering moisture brings respiratory ailments that are a bane to our domesticated birds.
