Bleached Grass

[SourRoses]

I’m thinking because the main two products are corn and soy that the glyphosate is killing it.

No. There's no way the level of herbicide would be high enough.

A lot of people don't realize how delicate a balance plants require to thrive. PH, nutrients, temperature at the roots vs foliage, etc.
We recently had a thread where someone was surprised their grass died after pouring hot water on it from processing.
I found myself surprised that they expected living plants to endure that.

Processed feed is rich in carbon, which isn't a bad thing except that without a proportional quantity of nitrogen, the carbon will suck available nitrogen out of the soil.
To help your lawn, you should fertilize it with a high-nitrogen fertilizer. But be careful! Chickens should not have access to the fertilizer, it can be dangerous. Wait until the area has been watered-in and given some days to sit before allowing chickens in the treated areas. It will take time for the grass in those spots to regenerate. You may want to reseed.

https://thegrowingleaf.com/remove-sawdust-from-grass/

Nitrogen Tie Up​

Although sawdust is widely perceived as a great mulch material for vegetable gardens, it’s also a fact that it can steal nitrogen from the soil as it decomposes.
Fresh sawdust is carbon-rich and can hold much moisture. When paired with the nitrogen-rich fertilizer commonly applied on lawn grasses and the abundance of moisture, this can spell disaster.
The soil microbes will become hyperactive and reproduce quickly because of the abundance of resources. This microbial activity can generate heat. Depending on the density of sawdust clumps, it can dehydrate or burn the foliage of adjacent grass.
Moreover, it can deprive your grass of the nitrogen it needs for healthy root growth and vibrant green blades. This is one of the most plausible reasons for the yellowing of the affected grass.

 

[SourRoses]

I looked up the feed and it contains licheniformis which does exactly what SourRoses said. It absorbs the nitrogen in the soil.

I hadn't considered that possibility, but you're right. In the link I posted above and quoted from, they mentioned extra microbial activity generating heat as another way high carbon material can kill the grass.