Hi,
The long stringy poops means your bunny is injesting hair. The hair it has injested is coming out. Is your bunny shedding?
Too much hair injested can be deadly, it can lead to GI Statis, here is a really good link, its a must read http://www.bio.miami.edu/hare/ileus.html
To help your bunny with the hair you can try combing him/her so they take in less hair. As well, hay helps with passing the hair out. Offer more hay or give fewer pellets to increase the amount of hay that is eatin to get the hair out.
If you see hair in the poo once twice not much to worry about, but if you keep on seeing it than its not good. I mean its good that it is coming out in the poops but it also means your bunny has alot of hair, if it doesn’t pass through the stomach can cause a blockage, which can be a serious problem.
What is oaten and Lucerne?
Timothy hay (or any type of grass hay like oat hay, brome, orchard, brumuda, meadow mix hay ) is the best one to give if you are worried about weight of the mother. For the babies alfalfa and timothy is good. If you feel mom is eating too much pellets then you can try feeding her seperately than the babies, seperate them at feeding time of pellets.
Too much pellets for older rabbits is not good it can lead to obesity, dental problems and generally is not healthy. The main diet should limited pellets, unlimited hay and veggies.
I have a mini rex and once he got seriously sick. I kept on seeing hair in his poop (long string poops) i kept combing him but it was too late. I guess at night he injested alot of hair while grooming himself. When i woke up he was cold, heard loud growling nosies from his stomach, kept moving around. From all the hair he took in he got a hair blockage and it didnt come out, this lead to GI Statis. He did not eat for around 15 hours, because his system was blocked with hair, and he was shaking aswell. When i took him to the vet she gave him some fluids and told me to give him fresh pineapple juice squeezed 3 times daily for 3 days until he gets better. She said if he does not recover within the next day could die!! Luckly, after about 4 hours he started getting better, and in about 2 days fully recovered.
Now anytime i see hair in his poo i try to prevent it by combing him more often as i dont want him to go through that again.