Hi , i am new to the forum and i have a bit of a concern with my budgie, his name is bert and is 6 years old, he is very chirpy and up beat , talks ALOT , plays with his bells , toys etc , over the past couple days i have noticed his poo a bit watery and slightly green, he still acts normal , not puffed up etc , in the morning there was a long string of poop attached to his vent , i took him to the vet today and they could not find anything wrong , they checked his poop and found no worms , but they did sugest i worm him as he has not been wormed for some time , ive attached some photo's , any advise would be appreciated , thank you