Any bird that has large dropping its usually an indicator that she has gone broody.. has she been sitting on a nest longer than usual... they hold droppings until they get up to walk about
Did she sleep on a nest all night ... as they usually do dropping throughout the night... it will be either one of these reasons why she had such a large dropping
Nothing to worry about
If she is going broody.... and you don't want her to hatch or you don't have a rooster there for you don't have fertile eggs... you will need to put her into another section without any nests or nesting material... some place safe and warm of course... out of the elements... but out of her normal routine ... leave her in this area for 3 days.. make sure she has plenty of food and water...
Return her to the flock after 3 days... if she returns straight to a nest.. return her to the isolation area for another 3 days.. same process..
The longer you allow a broody hen to sit on a nest if it has eggs or not... the longer it will take her to get over being broody... she will not eat properly and she will not drink properly... if she has one louse... then with her body temperature rising this will multiply into 1000 within 2 days.. so remember to dust her with a poultry dusting powder... don't spray her she won't dry properly as she won't be moving around enough
Also remember to secure the food and water... when they are put into isolation when broody they tend to have temper tantrums... and tip over anything they can
If she is in full broody mode.. she will scream.. yell at you .. curse you... refuse to eat for 2 maybe even 3 days... just keep the food and water ready for her when she is ready to eat and calm down... and ignore her as best you can
She will also pace up and down ... don't watch her it will drive you crazy.. and stress you out .. I know..