What motifs can be seen in act 2, scene 4 of Macbeth?

When Macbeth kills King Duncan, he commits a crime against nature. According to the ladder-like depiction of natural organisms in the world, called the Great Chain of Being, kings are naturally closer to God than other mortals. Further, the divine right of kings establishes monarchs as chosen by God to rule, making regicide not only a crime against the country but against God and nature as well. In act 2, scene 3, Macbeth seems to acknowledge this when he describes Duncan's dead body:

Here lay Duncan,His silver skin laced with his golden blood,And his gashed stabs looked like a breach in nature For ruin's wasteful entrance [...]. (2.3.130–133)

To Macbeth, then, the sight of Duncan's body is so horrifying and unnatural that he says the stab wounds look like wounds in nature itself. Then, in the next scene, this "crime against nature" motif continues. Ross remarks,

By th' clock 'tis day,And yet dark night strangles the traveling lamp. (2.4.8–9)

In other words, it is daytime, and yet it is pitch dark outside. This is certainly unnatural. The Old Man responds,

'Tis unnatural,Even like the deed that's done. On Tuesday lastA falcon, tow'ring in her pride of place,Was by a mousing owl hawked at and killed. (2.4.13–16)

He recognizes how unnatural the darkness is—just like the act of murdering the king is unnatural. Then he says that he saw a falcon attacked and killed by a much smaller and weaker owl. This, too, seems quite unnatural. Finally, Ross and the Old Man discuss how Duncan's horses seemed to turn wild and break out of their stalls to "Make war with mankind" and then "eat each / other" (2.4.22, 23–24). All of these unnatural occurrences seem to happen as a result of Macbeth's crime against nature, the regicide that has upset the natural order, and they can all be interpreted in ways that draw attention back to this original crime.