Poppies are rarely bothered with pests, so the first thing I would think of would be wind damage--the buds can whip right off when the wind is at the right velocity to rock the stems back and forth at the right frequency. Other possible culprits are rabbits or deer, but they have to be pretty desperate before they will touch poppies. If these are publicly accessible, they may be damaged by children (of all ages), what we in the nursery trade call "finger blight". It may be worthwhile staying up at night to see if there are slugs or caterpillars at work.

thanks for the suggestions, i have now seen that its squirrels that have taken a liking to the poppies. Pesky things.

Great! Stoned squirrels! Get those pictures out of my head!!