High solids content slurry, systems and methods. The slurry comprises a carrier fluid and a solids mixture of first, second, third and fourth particle size distribution (PSD) modes wherein the first PSD mode is at least three times larger than the second PSD mode, which is larger than the third PSD mode, which is larger than the fourth PSD mode, and wherein at least one of the second and third PSD modes is less than 3 times larger than the respective third or fourth PSD mode. The method comprises forming the slurry, positioning a screen in a wellbore and circulating the slurry through the wellbore such that the solids mixture is deposited between the screen and the wellbore. The system comprises a pump to circulate the slurry, a workstring to position the screen and means for converting the slurry to a gravel pack.