When I was in college in Colorado, I had tons of Blue jays at the house I rented and fed them raw peanuts, they picked them up whole and would fly up into the trees to tear them apart and eat, or hide them for later.
Dan

i see grackles foraging in lawns for bugs in small groups looking for bugs, sorta like starlings

My experience is that feeders draw junk birds--sparrows, pigeons, starlings. My next-door neighbor who puts up feeders always has a yard and roof crowded with them. I do not put up feeders, and my yard, heavily planted with a wide variety of native plants, is filled with jays, robins, cardinals, catbirds, mockingbirds, goldfinches, house finches, native sparrows, titmice, chickadees, . . .

Funny--we tend to get grackles AND jays in nearly equal amounts at the feeders and in the bushes. I like the grackles, personally--they actually chase off the starlings but let the cardinals and chickadees and finches be. Maybe you just have a really rude crowd? ;) You might try switching bird food; perhaps consult some books for reference (sorry I don't have any specific suggestions for you).
Or, switch to a feeder the grackles can't use due to their size and feeding habits? There are ones made specifically for certain birds--finch feeders e.g.
Good luck...

I love Grackles; they are as bold as brass! I love listening to them whistle, crackle like electricity, trill, pop and they way they strut around. They are so comical! I don't believe in "trash birds" anymore than I believe in weeds.

I love my Blue Jays...but love my Grackles too. My Blue Jays love peanuts in the shell, so do the Grackles but they take their peanuts to the birdbath to soak them before eating.
Blue Jay's love sunflower seeds & cracked corn - most anything, Grackles do too.
I love all birds, they are all welcome at my feeders including the two little Parakeets that have been regular visitors the past two weeks, what cuties!

Kittysmith's vocal discription sounds like a European Starling to me. Those of us familiar with the Common Grackle know it's song is little more than the sound of a rusty hinge.
Being human, there are definitely things that I don't care to have on my property. Right now the Japanese beetles are terrible, I can't remember a July without them. If I never see rats again it will be fine with me. European starlings and house sparrows are little more than feathered vermin. We can either discourage these birds and have a greatly improved environment or live in a "Polyanna" world, its a choice each one of us has to make.
Sam

Thanks Sam, but the birds in my yard in Houston are 100% Grackle, not Starlings. Beauty is in the ear of the beholder...or something like that!

Don't forget there are three kinds of grackles in North America. Somewhere around Houston is the fuzzy line between Boat-tailed Grackles and Great-tailed Grackles. The other is the widespread Com. Grackle which is found everywhere in the east. Of the three I think Great-tailed Grackle is by far the noisiest, especially at dawn when they really can raise a racket.

My question about Denver is: have Great-tailed Grackles become common there? They've been moving north and west for years, but I wasn't aware they had become a common feature of the Denver area. Or are you talking about Common Grackles?