when to leave grazing muzzle off?

Nov 4, 2008
752
18
18
just wondering when i should leave the grazing muzzle off my cob, he has had it on 24/7 during summer but has seemed hungry (although what cob isnt! haha) when he has been out of field e.g he never used to snatch for grass out hacking but has over the last week, so wasn't sure if the feed content or something has dropped so he isnt getting enough anymore?
 
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