There is some evidence to suggest that omega 3's are helpful for allergies and asthma at least for dogs, cats, and people.
At least in dogs and cats, combing antihistamines with omega 3's, is more effective than antihistamines alone.
I gave her fish oil capsules in her feed yesterday. She made a lot of faces, but ate all her grain anyway so it must not have been too terrible. I was really surprised she thought it was edible! I didn't even try to disguise the taste.
I will have to call the feed companies and see how expensive flaxseed is. If I buy pure flax oil, it comes out to about $18 a month. One ounce of oil is the same as feeding 1/4 th a lb of flaxseed.