Green’s Dictionary of Slang

hogan n.

[? fig. use of SE hog, to eat greedily; Dr Walter Bergdorf suggests: ‘don’t you think this comes from the name for a Navaho stone and dirt house, now used mainly for ceremonial purposes. They are dome-shaped and easily visualized as breasts’]
(US)

1. in pl., the female breasts.

[US](con. 1940s) M. Dibner Admiral (1968) 229: He admired the mound of her breast in splendid isolation. With hogans like that, he thought, who needs the Taj Mahal?
[US]Baker et al. CUSS 137: Hoagons The female breasts.
[US]G.V. Higgins Bomber’s Law 145: Donna ventre, that junior cheerleader with the gorgeous hogans on her.

2. (also hogen) a mouthful, used as a unit of measurement when describing the size of a woman’s breasts, therefore often in pl.

[US] ‘Cadet Sl. in the Air Force Academy’ Current Sl. II:2 17: Hogen, n. Unit of measurement equal to one mouthful.
[US]National Lampoon Oct. 100: Bending over so that great cubic hogans of boze [breast] were displayed [HDAS].

3. in pl., a young woman.

[UK]J. Quirk No Red Ribbons (1968) 80: I pulled that on some Hogans when I was an enlisted man.