My son was taking the lurchers out he let them run up a small hill and over the top time he got to the top my bitch was laying flat out , she was always the clown , nut job trying to trip her sister up turns out she had ran straight into her sister my son carried her home over her shoulders and she was wheezing couldn't get a breath took her to the vet and she had a collapsed lung they drained a pint and a half of air out one side and a pint out the other then wanted to keep her in . Only to get a phone call the next morning your dog cant walk we want to put her down a swear word and a off l