No.
Did the chickens accidentally eat something that the man intended for another purpose?
Was the other purpose for what they ate to be used as food (for any living thing)?
Was the other purpose for what they ate to be used in growing crops?
Was the other purpose for what they ate to be used in some kind of construction application - paving a road or installing some kind of fencing, for example?
Was the other purpose for what they ate related in any way to agriculture?
Was this the farmer who fed his chickens marijuana to treat them for worms?
No to all.
No.
Was the man being paid to give the substance to the chickens?
I’m not sure. Probably yes.
I’m going to call it due to the boring nature of the situation and because it has lingered.
**Henrik Dam fed chickens a low cholesterol feed as an experiment. They hemorrhaged blood from wounds and because of this, he discovered what would come to be called Vitamin K, which the chickens were deficient of.
He was awarded the Nobel Prize for medicine.
**
Uh, I tried to answer accurately. Please feel free to pick apart what I did wrong. 
Well, for starters, you said that he didn’t think that what he fed them would be chicken feed.
Yes, I think this was where we went off the rails:
O.K., this one is a little weird, it’s just something that came to me.
I know someone who has a strong motive to murder to my parents, even though this person has never met my parents and is unaware of the motive. Who is it?
Is inheritance involved?
Is the person as yet unborn? Is the person a child?
Answers embedded.
Apologies for accidental misdirections.
I don’t get what he was trying when he gave the chickens low-cholestorol food. I should have said “yes” to the food answer, though.
Is the person adopted?
No.
The owner of your parents’ insurance company, on the assumption their life insurance policy doesn’t pay out in the event of murder but does in the event of natural death.
No.
Is it your child, who has been named as a major beneficiary of your parent’s Will but doesn’t know that yet?
Would this someone benefit if your parents died in some way other than murder?
Would this someone also benefit if someone other than your parents were murdered?
Are there a large number of people (say, greater than 10) whose murders would also be beneficial to this someone?
Would it benefit this someone if only one of your parents were murdered?
Would it benefit this someone if a third party murdered your parents?
Answers embedded.
No.