It isn’t easy to aspirate fluids out of a stomach/crop even when we are talking cows with a 40 gallon stomach, a chicken with a couple mls will be very difficult and won’t make an appreciable difference to the animals health while the stress caused is probably counter productive. It makes you feel good but doesn’t help the bird. Between soft tissue clogging the tube which you then bruise and make even more edemetous, semisolids dissolved in the liquid which interfere with suction, small fluid volume, and the risk of aspiration pneumonia or trauma to the trachea/esophagus and minimal if any therapeutic effect, this is a bad idea.