Demand and the commodities market!

The grocer can't do anything about it.

All grain prices are up 30-50 percent in the last year or so.
Wheat may ease a bit because Russia expects a good harvest, but the trend will continue upward.

Salmon and all fish are up as a result of scarcity- over-fishing and possibly climate change.

China, India, Brazil, etc. are all taking more food as they develop larger middle classes.

The only answer is for people to stop or at least decrease breeding of new bodies to feed.