Degrated grains

What is a degrated grain? How have I decided it a grain is degrated or not? Merely subjectively! It just looked odd or bad and I put them aside. Some of the grains were very small, looked bad, had small wholes or were very dry. A few were eampthy inside, others looked like they not were developed fully. Some had most likely some fungi on, others had perhaps been eaten by snails as there was some on the spikes as well. 

I did not calculate these grains into the total amount of grain yield as I am not sure that they will germinate. Out of 116 spikes 34 spikes had some bad grains, which is 29%. All together it was 87 bad grains. 80% of the bad grains were only 1-3 couple per spike, some of them were located in the top of the spike. Only one spike had 10 bad grains of a total amount of grains 31 (so 1/3 were bad in this spike).