Narrow veal crates cause tremendous suffering for calves. The situation has improved in recent years: they are illegal in the EU, and while they are still legal in the US and in other parts of the world, a number of US states have banned or restricted their use. Some of the top veal-producing companies in the US, including Strauss Veal, have voluntarily phased them out in favor of higher welfare alternatives.
Calves kept in crates are typically fed an unhealthy diet of milk with no (or far too little) solid food in order to keep their flesh pale. This diet prevents their digestive systems from developing properly and can cause the calves to become dangerously anemic.
There are more humane alternatives that take into account the welfare of the calves.