Helpful Weed for Rabbits

This weed has been growing well in our yard for many years, still don't know the name.   

 

This is what it looks like when pulled from the ground.    I have asked around, tried google but could not find a name for it.   Why do I want to know the name?

This weed is wonderful for rabbits.

When rabbits don't eat well, take off their long wool and put them in the area with these weeds, they'll nibble and eat and exercise.

It seems to help clear the rabbits' internal systems.

And gives the rabbits more energy.

The only drawback is that these weeds only grow in late winter and spring.  When summer comes, they are dried out and disappear.

The two naked French Angora sisters Monique and Simone enjoy these weeds as much as possible during the growing season.