In chapter 5 of Of Mice and Men how does Steinbeck present the atmosphere in the barn following the death of Curley's wife?

Steinbeck uses light and animal imagery along with physical descriptors to show significant parts of the atmosphere presented in the barn following the death of Curley's wife.

As chapter five opens, the barn is mostly dark with some light interspersed. These slivers of light occupy the initial description before we see Lennie: "The afternoon sun sliced in through the cracks of the barn walls and lay in bright lines on the hay."  The atmosphere of the barn changes when Lennie kills Curley's wife. The imagery of light is one way that Steinbeck is able to show this atmosphere in the barn.  Once Curley's wife dies, Steinbeck writes, "The sun streaks were high on the wall by now, and the light was growing soft in the barn. Curley’s wife lay on her back, and she was half covered with hay."  From light "slicing in" to "growing soft," Steinbeck uses the description of light to show the atmosphere of the barn following the death of Curley's wife. 

Steinbeck shows another change in the atmosphere  presented in the barn through animal imagery once Curley's wife has died. The puppy is already dead and buried in the hay. When Lennie is talking with Curley's wife, there is a symbolic connection to the puppy while he pets Curley's wife's hair until he kills her. Lennie is scared of what he has done and of George's reaction. Steinbeck changes the atmosphere presented in the barn from excitement to fear through animal imagery when Lennie uncovers the dead puppy, grabs it and runs from the barn.  

Another significant change in the atmosphere uses animal imagery. Steinbeck had used animal imagery throughout the book and again in the description of the barn's atmosphere associated with the pigeon.  The pigeon flies in, then leaves.  The dog smells the dead body, then goes back to protect her puppies. These are examples of how animal imagery presents a shift in the atmosphere presented in the barn.

In addition to light and animal imagery, Steinbeck suggests that the atmosphere changes in the barn with Curley's wife herself.  Curley's wife lies in the hay with a subtle beauty:

Curley’s wife lay with a half-covering of yellow hay. And the meanness and the plannings and the discontent and the ache for attention were all gone from her face. She was very pretty and simple, and her face was sweet and young. Now her rouged cheeks and her reddened lips made her seem alive and sleeping very lightly. The curls, tiny little sausages, were spread on the hay behind her head, and her lips were parted.

Steinbeck accentuates this beauty to give her a sense of dignity and grace in death, which she could never experience in life.  This imagery of Curley's wife accentuates the change in the atmosphere presented in the barn, and provided as a foreshadowing of Lennie's fate, by symbolizing finality.