This really sucks. (Is it allowed to say so?)Two hours of freedom. Five hours of my day providing it.
Did you ever consider/ try to rehome the chickens to an allotment or another garden nearer to where you live.
2 times more than an hour is too much, whenever there is a problem with your health, if you ask me. 2x more than 2 hours is undoable. Especially if you are not fit.



Just thinking out loud:
Maybe there is a place nearby where chickens can be part of a national trust? Or someone near, who has an enormous garden who likes help with gardening and loves chickens too? A city park with animals? A children’s zoo? A park near a home for sick or elderly.