You could feed them from now until the foliage dies down once a week/fortnight with a liquid feed such as Phostrogen. Maybe they weren't planted deep enough initially & have suffered in dry conditions but you won't know unless you dig them up in about 6 weeks time & replant. The soil needs to be at least twice the bulb height above them..ie if the bulb is 2" big there needs to be 4" above it. Hope that makes sense.
To be honest, I've never managed to revive blind bulbs & at the price you can buy them for nowadays I'd rather plant new ones in Sept.