Flowers broken off...HELP

My sunflower plants are growing terrifically.....except that on many of the stalks, the flower breaks off before blooming completely. What is causing this????? What can I do to prevent this????? Many, many thanks in advance for any help!

I don't know if this applies in your situation but in my yard the rabbits are breaking the black-eyed susan stalks and leaving them lying all over the place in order to eat the petals...pesky wabbits! And they're baby bunnies too so I have a hard time staying mad...but I'm getting there! In another strand there was mention of something called "rabbit scat"? I may be wrong on the name. I'm sure someone else is more knowledgeable about deterring rabbits. I've been befriending them.

Yes, the bunnies have been doing the same to my black-eyed susans, but I know they're not breaking off my sunflowers. The sunflower stalks range from 2 ft to 6ft tall. The flowers are usually broken off at the very top of the stalks. It's making me nuts.

DO you have any squirrels? The squirrels always do this at my place. Dixie

We have bunches and bunches of squirrels. Do they climb up the stalks? Or.....?

Yes at my place they climb the stalk and cut the seed head down. Ive watched them do it,I always like sun flowers in the birdfeeder area and this is what always happens.
Dixie

Okay, one more question.....do the squirrels at your place cut off the seed head before the flower has completely bloomed? Mine just begin to open, and then BAM! Are the squirrels just too impatient to wait before the flower actually forms the yummy seeds?

Yes sometimes they do take them down before they are completly open. Mostly after they open up but the seeds are never mature.
Dixie