That's very interesting.
I've just been reading thro' the Grass & Root Seeds catalogue from our local ag merchants, Wynnstay, and they show chicory as an optional addition to most of their grass seed mixes. They also say about chicory ' Those finishing lambs in mid summer have seen big improvements from using chicory. When grass growth slows down in kid summer the chicory will maintain it's growth and farmers ....... nearly all report an outstanding increase in (lamb) growth rates.' If true then it looks worth considering when re-seeding.