She is 20 weeks old, wormed and treated for mites 2 months ago. She and the 3 others are healthy and I let them out for a free range for 2-3 hours each afternoon. She was fine about 4pm but just now I notice she is holding one eye shut, even though she is walking round and eating in the garden. She opens it from time to time briefly. It is kind windy now and my husband and I just got showered with old fir needles from the big tree. Could she have grit in her eye? Should I wash it out with human eye wash? Any other advice? Thanks so much. They''ll be in bed in 20 minutes so wanted to know if there's anything I should do now - or wait and see how she is in the morning.