To eat animal protein or not is a personal choice each person will make for themselves. I enjoy eating some poultry, lamb and beef, in moderation. This provides me with a good protein source. When I eat it, I enjoy it.
It is important to find animals, whether it be cows, chickens, sheep, etc. that are being raised by farmers that are concerned for the welfare of their animals. It goes without saying that animals who are not exposed to pesticides, antibiotics and other unhealthy lifestyle habits will be a source of health for those who, in turn, consume them. The quality of the animal's life is an energy that will be passed on eventually, to the consumers of their meat. If you know a farmer whose practices support either organic care or at least concern for their flock and/or herd, allowing them to roam outside in the fresh air and sunshine, and feeding them a grass-fed and/or grain-fed diet, then this would be your best source of meat.
The quality of the soil and grass that the animals are fed from are important factors inproviding the proper minerals and vitamins necessary for health. Poor quality meats, full of pesticides and antibiotics, have been attributed to elevated blood levels of the amino acid, homocysteine, which can be a risk factor for heart attacks, strokes and blood clots. However, a good quality red meat can also be a natural source of another amino acid, arginine, which is helpful for inhibiting fat absorption and reversing high blood pressure.