What's your question? Ask

It is either rabbits or something deer like. This can help with rabbits:
https://www.gardeningknowhow.com/plant-problems/pests/how-to-keep-rabbits-out-of-gardens.htm

I am not familiar with antelope, but if they are like deer, predator urea may work as will fishing line set up around the plant. You don't need much, just enough so they run into it with their nose. Because they can't see it, it makes them nervous and they leave the plant alone.

Yes, shasta daisies often rebloom several times throughout the growing season with regular deadheading.

They won't die if you leave them. In rare cases, rootbound plants put into the ground will continue to grow in a circular pattern that then strangles the root ball, but this does not usually happen. In most cases, even if the plant is rootbound when planted and the roots are not loosened, the root ball will in most cases spread out and grow just fine.

If you are still worried, you can just use a spade and plunge it into the soil around the plant in one or two locations to help break up the root ball.

Most likely over watering - Are the daisies planted close together? Mine still do the same because they multiply like rabbits!
I've given a bunch away, and transplanted even more...each year they keep popping up!
ALWAYS remove the yellow/spotted leaves ASAP - could be mold which spreads. I cut down to about 6" in fall, then in spring when they show signs of growth start dividing! PS - mine grow in sun and shade, and can get very tall!

Hope this helps!

In many areas, it has been very hot and, while shastas are normally very drought tolerant, this browning could be caused by too little water to deal with the heat.

It may also be a fungus.

I would recommend watering them some and then treating them with a fungicide to be on the safe side.

Treat the plants with neem oil. This will help prevent the eggs from attaching to the plant. It will also take care of any that may already be there.