Death in the trenches were a constant companion to those serving in the line, even when no raid or attacked was launched or defended against. In busy sectors the constant shellfire directed by the enemy brought on random death, it didn't matter whether their victims were lounging around in a trench or laying in a dugout. Similar novices were also cautioned to, like the parapet of the trench of No Man's Land. Many men died on their first day on the trenches because of the sniper bullets precisely aimed at the trenches. It has been estimated that up to one third of allied casualties on the Western Front were actually kept in the trenches. Besides all the injuries, diseases were a heavy toll.
Rat infestation was the worst, their were over a million rats infested in the trenches. There were 2 main types of rats the black and brown rat.. Both were equally despised but the brown rat was especially feared. Goring themselves on human flesh disfiguring them by eating their eyes and liver. They could grow to be as big as the size of a cat. Men were really afraid of these rats, they would even run across their faces in the dark. They would try to get rid of them gunfire, with the bayonet, and even by clubbing them to death. It was useless though, a single rat could produce up to 900 offspring in a year contaminating food and spreading infection. This problem continued for the rest of the war.
Although rats were a huge nuisance, lice was an even bigger problem breeding in the seems of dirty clothes and causing men to itch out of control. Even though clothes were washed constantly lice eggs remained in the seams, within a few hours of the clothes being re-worn the body heat would cause the eggs to hatch. Lice caused a very painfully disease that began with severe pain followed by high fever called Trench Fever. Recovery from this disease took up to 12 weeks. Lice was not actually identified as the cause of Trench Fever until 1918. Frogs were also found in the base of the trenches along with slugs and horned beetles on the side of the trenches. Many times men would shave their heads to prevent another prevalent scourge. Trench Foot was another medical condition affiliated with the trench life. It was a fungal infection on the foot caused by cold, wet and unsanitary trench conditions. In some cases it would have to lead to amputation. Trench foot was more of a problem of in the beginning, as conditions improved in 1915 it faded quickly.
Typically, a battalion would be expected to serve a spell in the front line. This would be continued by a stint spent in support, and then in reserve lines. A period of rest...