Feeding chickens/sheep together

I just got my first chickens (3 hens and a rooster) and I also have 2 new sheep.  I am trying to figure out what feeders to use to keep sheep out of the chicken's feed. 

My set-up is the chickens have a small penned area in my barn to sleep where they can come and go through a chicken door.  There is a fenced barnyard right behind the barn.  Then 3 gates are installed to lead out to different paddocks of pasture for sheep and chickens to graze. 

I was advised not to keep chicken feeders in barn where chickens go in at night because it will attract mice and the area isn't that big.  So I keep feeders in the barnyard.  However, sheep come in this yard as well.  I am planning to milk them on a milking stanchion sitting there. 

The feeder I bought is galvanized metal and it looks a bit like a top hat.  I am wondering why there is no lid on it covering the top.  The water feeder (which is similar) has a lid that fits over the center pipe where you keep the water. 

I would appreciate any ideas for chicken feeders where sheep can't get in it.  Also, so far the chickens have not gone out in the pasture at all.  They are perfectly content in the barnyard with their chicken feed and food scraps!  I want them to forage...

Beth

keep the feed inside and get a couple good barn cats.

Remove the feeders completely (or close them up, or leave them empty) for most of the day so that if they want to eat they have to forage.  We've done this with some hybrid broiler chickens that we bought who would attempt to spend all day lying down with their heads in the feeders.  The soon got the hang of the idea of having to move around if they want to eat. 

Thanks for the advice.  I will do both the suggestions! 

I let the chickens out into my raised bed garden yesterday and they loved being there, but they would have totally decimated the beds by their scratching if I left them there very long.  They were SO HAPPY though!  There were dirt and straw flying through the air as they scratched and picked through the beds.  I wish they could be there some but I need to keep my beds raised.  I don't use structures to hold the beds in place...just lasagna style.

Beth