Shiny odds for research quest encounters?

The only shiny pokemon I ever got from doing researches is squirtle, but that was thanks to the boost of shiny during community day.

I have caught tens of Mareep this month but none of them is shiny. Occasionally caught some Granbull, Houndour, Larvitar, Gen 1 starters and no shiny as well.

I caught 4 Absol through research encounters and had one as a shiny, but I've not had luck with anything else. I guess TSR are looking into this as part of their shiny research though.

The Silph Road did some research and the chance of a shiny from a quest is something like 1/60 I think.

Wild catches, outside of community days (and other specials, like the Roselia weekend), is supposed to be about 1/500.

Shiny odds for most species is exactly the same from research or wild. Magikarp, starters, Eevee, Larvitar etc. I've done a ton of research and gotten 1 Bulbasaur out of these "normal" shinies.

Event quests may have heightened chances of shinies, so far this has applied to Aerodactyl and possibly Pineco. Those odds were 1/60 for Aerodactyl like Skywalkered said, no data yet if Pineco has the same odds.

Squirtle CD research was special, as randomly decided stops would give a shiny sunglass Squirtle for everyone.