Dove and pigeon are the most known vectors of,Trichomonas gallinae. This is a protozoan parasite that causes Trichomoniasis (canker), one of the most nasty disease in chickens! You should try to avoid them from getting near your floc!
See this link...
Miss use of Antibiotics can cause a disruption of the chicken microflora. The antibiotics kills all the good beneficial microbes that keep the fungi ( which antibiotics do not affect) in this case the use of antibiotic can cause a yeast infection in the chicken crop and digestive tract! If you...
It is defently a cactus. Did you check her crop? To me she seems that she is gasping for air! It could be gape worm blocking her air ways!
When did you dewormed here?
Reed this link
http://www.flytesofancy.co.uk/chickenhouses/Worming_Poultry.html
I have used Mebendazole (vormex) 30 mg/kilo...
Are you shore that the plant is cactus and not a spurge?
The spurge family could be poisons! When you broke a limb it ooze milky juice?
See thus link...