I would not turn out on the grass as pictured unless you had no other options. It's too early.

My general rule of thumb in rotational grazing is to put them in when the grass averages 10" high and move them when they graze it down to 4" high. This leaves plenty of leaf area for the plant to recover quickly for the next time.

In the spring with grass growing quickly I turn in at about 8" and out at 4" with smaller areas and move them through quickly to keep the grass from getting out of hand and going to seed where it loses quality quickly.