How much shade they are in will affect how well they bloom. Rather than being shade lovers, hellebores are shade tolerant and there's a big difference between the two terms. Best flowering will occur where the plants get at least some direct sun - in most climates this will be morning sun - and many will grow very happily in full sun. Most species originated from areas that are quite open and exposed, like meadows and woodland verges.

FWIW, I have never found fertilizing to be necessary to encourage blooming. A good well-draining, organically rich soil is sufficient. If your plants are from seedlings, then it may still be early in their development for blooms. Generally it takes about three years from seed to achieve blooming maturity.