I haven't really "tested" hatching shinies out, but I feel like different pokemon have more chances than others. Eevees I barely got any, I got a lot of joltiks and chikoritas, a few litwicks, like two lapras', and probably some other mons.
I'm not entirely sure, but it might have to be day time(maybe morning). You could try setting your clock backwards a few hours and see if you find one, if the pokedex says it's there, it's most likely a time problem.